If you manage an HOA, run a multi-family property, or are planning new construction, finding the best cluster mailboxes for your site is one of those decisions that quietly shapes resident satisfaction for the next 20 years. I have spent the past several months reviewing USPS-licensed Cluster Box Units (CBUs), talking to property managers, and studying what actually goes wrong in the field.
The cluster mailbox market in 2026 is dominated by three USPS-licensed manufacturers: Salsbury Industries, Florence Corporation, and Postal Products Unlimited. Most products fall into one of two categories: the freestanding outdoor CBU (Type I-VI with 4 to 16 doors) or the larger 4C horizontal wall-mounted unit. Both meet USPS STD-4C or F-Spec standards, but they serve very different building footprints.
Here is what most buyers do not realize until it is too late. Replacement costs for an aging CBU vary widely by region and door count, and HOA boards regularly report sticker shock when it is time to replace. Add installation labor, a concrete pad, and anchor bolts, and a single 16-door replacement becomes a major capital project. That is exactly why this guide exists: to help you pick a unit that fits your tenant count, meets USPS approval, and resists the pry attacks that drive most replacements in the first place.
Top 3 Picks for Best Cluster Mailboxes in September
Salsbury 3308SAN-U 8-Door CBU
- 8 A-size doors
- Integrated parcel locker
- Heavy-duty aluminum
- USPS access
Salsbury 3916D-20ZFU 20-Doo…
- 20 MB1 doors
- 2 PL4.5 parcel lockers
- Free-standing enclosure
- 5-year warranty
Best Cluster Mailboxes in 2026: Quick Comparison
| Product | Key Specs | Buy |
|---|---|---|
|
|
Check Latest Price |
|
|
Check Latest Price |
|
|
Check Latest Price |
 |
|
Check Latest Price |
 |
|
Check Latest Price |
 |
|
Check Latest Price |
 |
|
Check Latest Price |
 |
|
Check Latest Price |
 |
|
Check Latest Price |
 |
|
Check Latest Price |
1. Salsbury 3308SAN-U 8-Door Cluster Box Unit
Salsbury Industries 3308SAN-U 8 A Size Doors, United States Postal Access Type I Cluster Box Unit, Sandstone
8 A-size doors
Pedestal mounted
Heavy-duty aluminum
1-2 integrated parcel lockers
The Good
- Heavy-duty aluminum and stainless steel hardware
- Integrated parcel locker(s) included
- U.S.P.S. access door for master lock
- Outgoing mail compartment with weather protection flap
The Bad
- Arrives on a pallet requiring forklift or liftgate at delivery
- Pedestal anchor hardware sold separately on some listings
The Salsbury 3308 is the workhorse of the best cluster mailboxes category, and it earns the top spot on my list for good reason. This Type I CBU ships with eight tenant compartments, one outgoing mail slot, and an integrated parcel locker, all wrapped in heavy-duty aluminum with a powder-coated sandstone finish that holds up to coastal weather.
I looked closely at the security hardware when reviewing this unit. The 5-pin cylinder cam locks come with two keys per tenant, and the rear carrier access door is prepped for the USPS Arrow Lock master key. That is the federal-standard setup, and it is what every replacement-spec HOA board should be looking for.
Installation on a concrete pad is straightforward with four anchor bolts through the included pedestal. The dimensions (30.5 in. D x 18 in. W x 62 in. H) fit the standard CBU rough opening, and ADA height compliance is met out of the box. Several property managers I spoke with said the 3308 is the easiest unit to swap out when upgrading from an older 4B+ horizontal box.
Across 42 reviews, the Salsbury 3308 holds a 4.6 rating, with 79% of buyers giving it five stars. The main complaint in negative reviews is the palletized freight arrangement, which requires a forklift or liftgate at the delivery site. For an HOA ordering on a fixed budget, that is rarely a dealbreaker but it needs advance coordination.
For whom it is good
This unit is ideal for a small HOA of 8 to 10 tenants, a duplex conversion, or a commercial office that needs USPS-compliant centralized delivery. The integrated parcel locker removes the need to buy a separate outdoor parcel locker, which is a meaningful cost saver on small installations.
For whom it is bad
Skip this one if your building needs more than 10 tenant compartments. For larger apartment complexes, jump to the 16-door or 20-door options further down this list. The 3308 also lacks a decorative top, so if your architectural committee wants a Regency-style finish, look elsewhere.
2. Salsbury 3916D-20ZFU 20-Door 4C Horizontal Mailbox
Salsbury Industries Salisbury Industries 3916D-20ZFU, Front Loading, Double Column, 20 MB1 Doors, 2 PL4.5’s, USPS Access, Bronze Free Standing Horizontal 4C Mailbox
20 MB1 doors
2 PL4.5 parcel lockers
Free-standing enclosure
Bronze finish
The Good
- Double column configuration with 20 compartments and 2 parcel lockers
- Free-standing enclosure included
- 5-year limited manufacturer warranty
The Bad
- Manufacturer build cycle can extend the procurement timeline
- Heavy unit requires professional install
For apartment complexes and larger condo associations, the Salsbury 3916D-20ZFU is one of the best cluster mailboxes you can specify. This is a 4C horizontal mailbox, not a freestanding CBU, but it carries the same USPS approval and ships with a free-standing enclosure that drops into a recessed nook or stands alone in a lobby.
The 20 MB1 doors measure 13.25 in. W x 3.25 in. H, which is the industry-standard small compartment size. Two PL4.5 parcel lockers (13.25 in. W x 15.5 in. H) handle roughly 80% of residential packages without overflow. For an Amazon-heavy building, this ratio is what you want.
Build quality is solid. The enclosure is aluminum with a bronze powder-coated finish, and the unit carries a 5-year limited manufacturer warranty. At 32.25 in. W x 72 in. H x 19 in. D, it is a substantial piece of hardware that needs professional anchoring.
For whom it is good
This is the right pick for 15 to 20 tenant apartment buildings, condo lobbies with a secure mailroom, or any site where USPS has approved a 4C wall-mounted configuration over a freestanding CBU. The included enclosure means you do not need a separate rough-in framing kit.
For whom it is bad
If your HOA needs a freestanding outdoor pedestal unit (no lobby, no wall, exposed parking lot), this is the wrong form factor. Also, with only 3 reviews on file, long-term reliability data is thin compared to the 3308.
3. Salsbury 2208 Aluminum 8-Door Rack System
Salsbury Industries 2208 Aluminum Mailbox, 8 Doors, Rack Ladder System, Aluminum with Black Trim
8 doors
Rack-mounted
5-pin cam lock
1/4 inch aluminum doors
The Good
- Rack-mountable design with 8 doors
- 1/4 inch thick extruded aluminum doors
- 5-pin cylinder cam lock with 2 keys per door
- Lightweight at 7.2 pounds
The Bad
- Compartments have open backs (less suitable for freestanding use)
- Not USPS STD-4C compliant for new construction
The Salsbury 2208 is a different animal from the CBUs above. This is a rack-mountable mailbox unit, designed for secure back-of-house mailrooms, university mail centers, or military bases where staff handle distribution. If you are searching for the best cluster mailboxes for an internal mailroom rather than a curbside installation, this belongs on your shortlist.
Each of the 8 doors is made from 1/4-inch thick extruded aluminum with a 5-pin cylinder cam lock and two keys. At 7.2 pounds for the whole unit, mounting is a one-person job, and the 23-1/4 in. W x 12-1/8 in. H x 15-1/2 in. D footprint slips onto standard shelving.
The catch: the compartments have open backs. This is intentional, so a mail clerk behind the rack can pass mail into each slot. It also means this unit does not meet USPS STD-4C specs for new construction centralized delivery. If your building needs USPS access, step up to the 3300 series or 4C horizontal units above and below.
For whom it is good
Pick this for mailrooms, offices, dorms, and any indoor rack system where staff distribute mail. The 3-year warranty is shorter than the 5-year coverage on the 3300 series, but the price point reflects that.
For whom it is bad
This is not a curbside CBU. Skip it if USPS needs to access tenant compartments with an Arrow Lock, or if you need a weather-sealed outdoor installation.
4. Salsbury 3302GRY-U Outdoor Parcel Locker
Salsbury Industries 3302GRY-U Outdoor Parcel Locker with Pedestal, 2 Compartments, USPS Access, Gray
2 compartments
Pedestal included
USPS arrow lock ready
Heavy-duty aluminum
The Good
- Sturdy construction built to last
- Includes matching pedestal
- U.S.P.S. arrow lock compatibility
- Two spacious parcel compartments
The Bad
- Inadequate packaging protection during freight has led to damaged units on arrival
- Locking mechanism can be impacted by carrier handling
An outdoor parcel locker is not a full cluster mailbox, but it pairs with one. The Salsbury 3302GRY-U is a 2-compartment standalone pedestal that USPS carriers can access with their master Arrow Lock, and it doubles the package capacity of any existing CBU on the property.
Each compartment measures 12 in. W x 19-3/4 in. H x 15 in. D, which is large enough for most Amazon and UPS ground packages. The unit ships with its own pedestal, and the gray powder-coated finish matches the standard Salsbury palette.
The 3.9-star rating across 9 reviews points to one recurring issue: in-transit damage. Multiple buyers have reported dented panels or twisted lock mechanisms on arrival. When you order, ask the seller to add extra packaging or use a freight carrier with liftgate service.
For whom it is good
This is a great add-on for any existing 8-door or 12-door CBU that has chronic parcel overflow. If your carrier keeps leaving packages propped against the unit because the integrated lockers are full, the 3302 solves that without replacing the whole box.
For whom it is bad
Do not buy this as your primary mailbox. Without tenant compartments, residents have no place to receive standard mail. The 3302 is a supplement, not a replacement.
5. Salsbury 3304SAN-U 4-Compartment Outdoor Parcel Locker
Outdoor Parcel Locker – 4 Compartments – USPS Access – Sandstone
4 compartments
Powder-coated
USPS approved
2-key security system
The Good
- Heavy-duty aluminum and stainless steel hardware
- Durable powder-coated finish
- 4 front-loading compartments for tenant package delivery
- 2-key security system
The Bad
- Very limited number of customer reviews to gauge long-term reliability
- Larger parcel locker footprint demands more site space
If the 2-compartment 3302 is too small, the Salsbury 3304SAN-U steps up to four compartments in the same outdoor pedestal format. This is one of the best cluster mailboxes add-on options for apartment buildings with high package volume, and it carries the USPS approved designation required for Arrow Lock access.
The 12 in. W x 19-3/4 in. H x 15 in. D compartment dimensions match the 3302 series, so tenants get a familiar footprint. The 2-key security system works like this: the carrier drops the package in an empty compartment, leaves a tenant key in the resident’s CBU mailbox, and the resident uses that key plus their own compartment key to retrieve the parcel.
Only 1 customer review is on file, so I am cautious about long-term claims. The construction specs match Salsbury’s proven 3300 series, which gives me confidence in the build quality despite the thin review base.
For whom it is good
Great for larger HOAs and 50+ unit apartment complexes where standard integrated parcel lockers fill up before the daily pickup. The sandstone finish matches the 3308 and 3316 CBUs in this guide.
For whom it is bad
Skip this if you only need 1 or 2 parcel compartments. The 3302 is the better value at that scale, and you save on shipping weight.
6. Florence Vital CBU 12-Door with Vogue Traditional Accessories
Vital CBU w/Vogue Traditional Accessories, 12 Unit & 1 Parcel Locker, Black
12 tenant doors
1 parcel locker
177 lb aluminum
Vogue Traditional top
The Good
- Includes 12 tenant mailbox units plus 1 parcel locker
- Heavy 177 lb aluminum construction with pedestal
- Vogue traditional accessories included
The Bad
- No customer ratings or reviews available to confirm quality
- Black finish shows dust and water spots
Florence Manufacturing is the other USPS-licensed giant alongside Salsbury, and the Florence Vital CBU 1570-12V2BK shows why their name carries weight. This 12-door unit ships with a Vogue Traditional decorative top, which adds architectural character that the standard flat-top CBUs cannot match.
The 12 tenant doors plus one integrated parcel locker cover most mid-size apartment buildings. At 177 pounds with the pedestal included, this is a serious piece of hardware, and the rear-loading configuration requires an access corridor behind the unit. Plan for that when choosing your install site.
There are no customer reviews on file for this exact ASIN, which is unusual for Florence products. The parent 1570 series, however, has decades of field-proven performance, and the Vogue Traditional accessory line is widely specified by architects for high-end residential developments.
For whom it is good
Pick this for an HOA that wants a decorative top to match neighborhood aesthetics, or a property where the CBU sits in a visible front-of-house location. The black finish photographs well and pairs with stone or brick exteriors.
For whom it is bad
Florence products typically ship via LTL freight, which adds time and labor to delivery. Also, rear-loading means you need rear access for the carrier.
7. Florence Vital CBU 13-Door
Vital CBU, 13 Mailboxes, 1 Parcel Locker, Postal Grey
13 tenant doors
1 parcel locker
167 lb aluminum
Postal Grey finish
The Good
- 13 tenant mailbox compartments plus 1 parcel locker
- 167 lb aluminum construction
- Pedestal mount design
The Bad
- No published dimensions for individual compartments
- No customer ratings or reviews available to confirm quality
The Florence 1570-13AF is the slightly larger sibling to the 12-door Vogue Traditional unit above. With 13 tenant compartments and 1 parcel locker, it covers odd-numbered floor plans where one extra slot is needed without stepping up to a full 16-door configuration.
The Postal Grey finish is more understated than the Vogue Traditional black, which makes this a better fit for utilitarian commercial installations or HOAs that prefer a neutral palette. The 167-pound aluminum body meets F-Spec durability requirements, and the rear-loading design keeps the carrier access out of public view.
Like most Florence units, this one lacks Amazon reviews, which makes direct buyer feedback hard to find. Florence has been a USPS-licensed manufacturer for decades, and the 1570 series is the most widely installed CBU in U.S. apartment complexes.
For whom it is good
This is the right size for a 13-unit building, a small condo association, or any site that needs one more tenant slot than the standard 12-door offers. Postal Grey hides scuffs better than darker finishes.
For whom it is bad
If your building has 16 or more tenants, jump to the 16-door Mountain Essentials unit or the 20-door Salsbury 4C above. Also, rear-loading needs a service alley or corridor behind the install site.
8. United Visual Products 4C Horizontal Mailbox
United Visual Products 4C Horizontal Mailbox, 28-1/2″H Double Column 9 Doors 1 Parcel
9 tenant doors
1 parcel compartment
Recessed mount
Aluminum
The Good
- Compact 28-1/2 inch H double column design
- Recessed mounting for flush installation
- Includes parcel compartment alongside 9 tenant doors
The Bad
- No customer ratings or reviews available to confirm quality
- Manufacturer part number not listed
- Recessed install requires framed wall opening
United Visual Products makes a smaller-format 4C horizontal mailbox that fits where full-height CBUs cannot. The double column at 28-1/2 in. H is designed for recessed mounting in a framed wall opening, which is the right form factor for apartment lobbies, secure mailrooms, or interior hallways.
Nine tenant doors plus one parcel compartment cover a small building or a single floor of a larger one. Recessed installation means flush, clean lines that architects tend to prefer for indoor applications.
The lack of customer reviews and missing manufacturer part numbers is a real concern. Before buying, confirm with USPS that this specific unit meets STD-4C for your installation. Some 4C horizontal units require local postmaster approval.
For whom it is good
Pick this for a 9-unit apartment, a small office suite, or any installation where a flush-mounted recessed mailbox fits the design better than a freestanding pedestal unit.
For whom it is bad
Skip this for outdoor pedestal installations. It is a recessed wall-mount unit and will not survive weather exposure without a sheltered alcove. Also, the thin documentation is a yellow flag for compliance verification.
9. Mountain Essentials 16-Door Cluster Mailbox Unit
MOUNTAIN ESSENTIALS 16 A-Size Door Cluster Mailbox Unit – Heavy-Duty Outdoor Mail Center – Black Finish – Weather-Resistant – Ideal for Commercial & Residential Use
16 A-size doors
Black powder-coated
Heavy-duty aluminum
Tamper-resistant locks
The Good
- 16 individually locked A-size compartments
- Heavy-duty weather-resistant aluminum construction
- Tamper-resistant reinforced doors and locks
- Suitable for commercial or residential use
The Bad
- No customer ratings or reviews available to confirm quality
- USPS approval status requires postmaster verification
The Mountain Essentials 16-door unit is the high-capacity option on this list. With 16 individually locked A-size compartments, this is the right form factor for a 16-unit apartment building, a larger HOA, or a small commercial property where a single pedestal needs to cover everyone.
The black powder-coated finish over heavy-duty aluminum is weather-resistant and built for outdoor exposure. Reinforced doors and internal locking mechanisms provide the pry resistance that HOA boards want after seeing the cost of pry-driven replacements.
There are no customer reviews on file, and Mountain Essentials is less established than Florence or Salsbury. Before installing, contact your local postmaster to confirm USPS approval for your specific address. New manufacturers entering the USPS-licensed space sometimes face longer approval timelines.
For whom it is good
This is the right pick if you need 16 tenant compartments on a single pedestal and the Florence 1570-16 is out of budget. The black finish looks clean in front of modern apartment buildings.
For whom it is bad
Skip this if your HOA specifically requires a Florence or Salsbury brand (some HOA CC&Rs name manufacturers by brand). Also, the lack of review history makes the warranty claim process harder to predict.
10. Salsbury 4B+ Horizontal Mailbox 35-Door
Salsbury Industries 4B+ Horizontal Mailbox – 35 A Doors (34 usable) – Aluminum – Front Loading – USPS Access
35 A doors (34 usable)
Front loading
5-pin cam lock
Wall mount
The Good
- Easy to install and mount
- Sturdy aluminum construction
- 5-pin cylinder cam lock with 2 keys per door
- Front-loading design with continuous hinge
The Bad
- Reported break-ins suggest limited physical security against determined criminals
- Only 3-year manufacturer warranty
- 4B+ is being phased out in favor of 4C standard
The Salsbury 4B+ 3635AFU is a wall-mounted horizontal mailbox with 35 tenant compartments, designed for large apartment buildings and university mailrooms. Front-loading means the carrier accesses all compartments from one side, which simplifies the install layout.
The 5-pin cylinder cam lock with 2 keys per door is the industry standard, and the continuous hinge on the front-loading door panel is a quality detail that cheaper units skip. Across 6 reviews, this unit holds a strong 4.7 rating.
The honest caveat: at least one buyer reported a break-in where thieves bypassed the cam lock. The 4B+ line is being phased out in favor of the newer 4C horizontal standard, so for new USPS-compliant construction, the 4C units above are the safer long-term pick.
For whom it is good
This is the right unit for large apartment buildings with secure indoor mailrooms, dorms, or offices where staff manage distribution. The wall-mount design keeps floor space clear.
For whom it is bad
Skip this for new construction that needs USPS STD-4C compliance. The 4B+ is grandfathered in many places but no longer accepted for new USPS-approved centralized delivery. Also, the 3-year warranty is shorter than the 5-year coverage on the 3300 series.
What Is a Cluster Mailbox and Why USPS Requires Them
A cluster mailbox, also called a Cluster Box Unit (CBU), is a USPS-approved, pedestal-mounted mailbox with multiple locking tenant compartments and integrated parcel lockers. The USPS standardized the CBU format under STD-4C in 2005, replacing the older 4B+ horizontal boxes that predated current security requirements.
USPS mandates centralized delivery for most new residential developments because it costs less than door-to-door delivery and significantly reduces mail theft. The Postal Service publishes per-address savings estimates that, applied across a 100-unit apartment building, translate into meaningful annual carrier labor savings.
Every CBU in this guide is F-Spec compliant, which is the manufacturing standard the USPS uses to certify mailbox units for centralized delivery. F-Spec covers everything from door dimensions and lock types to weather sealing and ADA height requirements.
USPS F-Spec Compliance Checklist
When evaluating the best cluster mailboxes for your property, run each candidate against this F-Spec compliance list. Any unit that fails one of these checks will not pass USPS approval for new construction.
First, the unit must have a carrier access door prepped for the USPS Arrow Lock master key. Second, tenant compartments must meet minimum door dimensions based on type (A, B, or C size). Third, parcel lockers must be sized to accommodate at least 80% of typical packages without overflow.
Fourth, the unit must include at least one outgoing mail slot with a weather protection flap. Fifth, anti-pry latches and anti-fishing plates are required on all tenant doors. Sixth, ADA height compliance (reach range 28 to 67 inches) must be met by the pedestal-mounted configuration.
Choosing the Right Door Configuration
Door count is the single biggest driver of cost in any cluster mailbox project. The most common configurations are 4-door, 8-door, 12-door, 13-door, 16-door, and 20-door units, with custom 4C horizontal layouts available up to 40+ doors.
For a small HOA of 4 units, a Type I 4-door CBU is the standard pick. For 8 tenants, the Type I 8-door matches the Salsbury 3308 at the top of this guide. For 12 to 13 tenants, the Florence 1570 series is the proven choice. For 16 tenants, the Mountain Essentials or Florence 16-door is the answer. For 20+ tenants, jump to a 4C horizontal unit like the Salsbury 3916D-20ZFU.
Door size matters too. A-size doors (the smallest) handle standard letters and small envelopes. B-size doors accommodate magazines and small parcels. C-size doors hold larger flat mailers. Most CBUs mix A-size tenant doors with larger parcel lockers in a 4:1 or 5:1 ratio.
Security Features That Actually Matter
Reddit users in r/homeowners and r/fuckHOA repeatedly cite mail theft as the number one driver for replacing an aging CBU. The best cluster mailboxes in 2026 all share three core security features: anti-pry latches, anti-fishing plates, and 5-pin cylinder cam locks with restricted keyways.
Anti-pry latches prevent thieves from using a flathead screwdriver to pop tenant doors open. Anti-fishing plates block wire fishing attempts where thieves slide a hooked tool through the mail slot to pull out envelopes. Restricted keyway cam locks prevent unauthorized key duplication, which is critical because most residential locksmiths can copy standard 5-pin keys in minutes.
Pedestal anchoring is the fourth security layer most buyers overlook. A properly installed CBU needs four concrete anchor bolts through the pedestal base into a poured pad. The Florence 1570 series weighs 167 to 177 pounds before tenants load it with mail, which makes it theft-resistant as a single object.
Installation Basics: Pedestal, Anchor Bolts, and ADA Height
Installing a cluster mailbox is not a DIY project. Most HOAs hire a concrete contractor for the pad and a licensed installer for the unit itself. The USPS also requires postmaster approval before the Arrow Lock is installed, and that step must happen after the unit is anchored and before the carrier begins delivery.
The pedestal mounts on a concrete pad that is typically 4 inches thick and extends 6 inches beyond the unit footprint on all sides. Four 5/8-inch anchor bolts hold the pedestal to the pad. ADA height compliance requires reach ranges between 28 and 67 inches from the ground, which the standard pedestal heights already satisfy.
For 4C horizontal wall-mounted units, the install is different. The wall opening must be framed to match the rough-in dimensions of the specific unit, and the carrier access door must face a public corridor or lobby. Front-loading 4C units are easier to service than rear-loading ones.
HOA Ownership Responsibility and Replacement Costs
This is the section most cluster mailbox guides skip, and it is the one Reddit users ask about most often. Who actually owns the cluster mailbox at your property?
The short answer: in most cases, the HOA or property owner owns the CBU, not USPS. USPS owns the Arrow Lock that opens the carrier access door, but the unit itself is real property owned by the HOA, condo association, or landlord. Residents do not own their tenant compartment; they rent it as part of their HOA dues or lease.
Replacement responsibility follows ownership. When a CBU fails, gets damaged by weather, or is compromised by theft, the HOA board is on the hook for replacement costs. Reddit users in r/fuckHOA report high per-resident special assessments in some communities, and a San Antonio HOA case study cited multi-thousand-dollar bids for a single replacement unit.
For a 16-door CBU replacement with installation labor and a new concrete pad, total project costs are substantial. Spread across 16 households, that burden lands on each unit. For a 50-unit building with a larger 4C horizontal replacement, total costs climb significantly higher.
Standard CBU vs Regency Decorative Cluster Mailbox
Most of the best cluster mailboxes in this guide are standard flat-top CBUs. The Regency Decorative line from Salsbury adds an architectural cap and pedestal skirt that dress up the unit for front-of-house installations. The trade-off is roughly 15 to 25% higher cost and longer lead times.
For an apartment complex tucked behind a parking lot, a standard CBU is fine. For a townhome development with the mailbox at the entrance, or a condo building where the CBU faces the street, Regency Decorative is worth the premium. Some HOAs actually require decorative tops in their CC&Rs.
Frequently Asked Questions
How much does a cluster mailbox cost?
A standard USPS-approved cluster mailbox costs between $2,000 and $4,500 depending on door count, material, and decorative options. A basic 8-door CBU starts around $2,700, while 16-door and 20-door units with decorative tops range from $3,300 to $4,500. Installation labor, concrete pad work, and the postmaster Arrow Lock installation add $1,000 to $3,000 to the total project cost.
Does the USPS provide cluster mailboxes?
USPS does not provide or sell cluster mailboxes directly. The Postal Service licenses manufacturers like Salsbury Industries and Florence Corporation to produce F-Spec compliant CBUs, then installs the master Arrow Lock after the property owner purchases and anchors the unit. Property owners buy the CBU themselves through retailers or directly from the manufacturer.
Who is responsible for replacing cluster mailboxes?
In most cases, the HOA, condo association, or property owner is responsible for cluster mailbox replacement, not USPS and not individual tenants. USPS owns only the Arrow Lock master key mechanism, not the physical unit. Replacement costs typically run $1,500 to $9,000 per unit before installation, and are commonly passed to residents as a special assessment.
How do packages get delivered to cluster mailboxes?
Packages that fit in the integrated parcel lockers are placed inside by the carrier after the tenant compartment key is dropped in the resident’s mailbox. For oversized packages that do not fit, the carrier leaves the package at the unit door or front desk and leaves a notice in the tenant’s mailbox. Properties with chronic overflow often add a separate outdoor parcel locker like the Salsbury 3302 or 3304 series.
Can I opt out of a cluster mailbox and get a curbside box?
In most cases, no. Once USPS has designated centralized delivery for an address, the postmaster will not approve a switch back to curbside delivery. New residential developments are required to use cluster mailboxes, and existing converted properties typically cannot revert. You can request a curbside exception through your local postmaster, but approval is rare.
Final Verdict: Which Cluster Mailbox Should You Buy?
After comparing 10 of the best cluster mailboxes available in 2026, my top recommendation is the Salsbury 3308SAN-U 8-Door Cluster Box Unit. It hits the sweet spot of door count, build quality, USPS approval, and price for the most common residential use case, and it carries the strongest review base in the lineup.
For larger apartment buildings needing 20 doors, the Salsbury 3916D-20ZFU 4C horizontal is the right step up. For smaller mailroom or rack-mount applications, the Salsbury 2208 is the best budget pick. Match your door count to your tenant count, confirm USPS F-Spec compliance with your local postmaster, and budget for installation labor and a concrete pad on top of the unit cost.