Cluster Mailboxes for Centralized Mail Delivery

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What is a Cluster Mailbox?

A cluster mailbox or cluster box unit (CBU) is a free-standing, pedestal mailbox with 8, 12, 13, or 16 individually locked mailbox compartments and up to 2 integrated parcel lockers approved by the U.S. Postal Service. Since all cluster boxes are USPS Approved mail delivery equipment, they are the most common community mailboxes on the market. (To view other commercial mailboxes, click here). They also come in six (6) different architectural colors and can be modified to fit any community design. The colors include Sandstone (our most popular), Black, Bronze, Gray, Green, and White.

Our US mail supply manufacturers equip every CBU with an outgoing mail slot and houses between one and two parcel lockers for package delivery (note: you can purchase an eight-tenant unit with up to four parcel lockers).

Installation: If you need someone to install your cluster mailbox, we offer installation options on each CBU product page. Choose the option that best suits your requirements for cluster units. After you place the order, we will send you info regarding the installation process and the next steps. For more details on our CBU installation program, please see this article. Once you install your CBU, you can contact your local postmaster to come out and install their proprietary Arrow Lock, which allows the mail carrier to deliver to all tenants.

Note: While the Cluster Mailboxes found on this page are pre-approved by the USPS for centralized mail delivery, customers may wonder if the same is true of 4C pedestal mailboxes. The answer is: no, 4C pedestal mailboxes require pre-approval by the USPS before you purchase and install if you intend to use them for USPS mail delivery. If you intend to use a 4C pedestal for private use, then this should not be a point of concern. If you have questions about this, feel free to give us a call. Update: as of November 2020, all 4C Pedestal Mailboxes are discontinued. The USPS spec cluster box unit is now the industry standard for outdoor pedestal mounted centralized mail receptacles.

Choosing the right Cluster Mailbox (CBU)

Are you looking for the right cluster box to fit your needs? We can help! We offer a wide selection at the lowest prices to meet your next commercial or residential development project's needs. If this is your first time purchasing a cluster box unit, below is some information you may find helpful. Of course, feel free to call us at (866) 707-0008 or open a chat window (bottom left of the site) with one of our reps if you need immediate assistance.

Options for USPS approved Cluster Mailboxes include:

The Standard CBU is USPS Approved

The following CBUs are already pre-approved by the USPS:

8 Door Cluster Box Unit
12 Door Cluster Mailbox
13 Door Cluster Box Unit
16 Door Cluster Mailbox

We also offer a 4-Door unit with larger doors (model # 1570-4T5) and an 8-Door unit with 4 parcel lockers (model # 1570-8T6) that are also USPS approved. If you are unsure which of these options best suits your needs, feel free to call and speak to one of our product experts. They can help you find the right unit within your budget. All clustered mailboxes come equipped with an individual compartment lock for complete mail security.

The USPS Approved F-series type Cluster Mailbox is available here in six different tenant door configurations and in six architectural color options among which to choose. We offer quantity pricing for two or more units, in addition to other CBU mailbox features (see individual product pages for details).

We always include pedestals.. Shop with confidence, and feel free to call, email, or open a chat with one of our product experts.

You can also see a similar selection in High Security and Decorative options below.

The High-Security CBU (also USPS Approved)

While our manufacturers build the standard cluster box to prevent theft, the High-Security pedestal option can significantly reduce the risk of mail and identity theft. You can purchase the vandal-proof fasteners to attach to the unit's anchor bolts for these units. The manufacturer has also designed the master front loading door to prevent prying, making it nearly impossible for mail thieves to break open the master door. In general, the latest industry-standard Cluster Mailboxes boast a thicker, reinforced metal gate with a larger diameter hinge rod on all tenant doors.

Ideal for university mailing (and other applications), shop cluster mail box units approved by the U.S. Postal Service. Both Florence Corp. and Salsbury Industries boast the largest CBU mailbox inventory in the United States, and we are proud to be their online suppliers. Between both manufacturers, the architectural spec sandstone cluster box units are the most popular.

The Decorative CBU (also USPS Approved)

Decorative CBUs are identical to the standard units, except for the Pedestal and Cap. For Auth-Florence models, you can choose either the Classic Decorative unit or the Traditional Decorative unit. For Salsbury models, you can select the Regency option. Images of these three options are displayed below. The Florence CBU boasts two decorative styles. Shop Florence Commercial Mailboxes to view these styles and options.

Classic Decorative Cluster Mailbox Traditional Decorative Cluster Mailbox Regency Decorative Cluster Mailbox

4C Pedestal Mailboxes

Note: All manufacturers of 4C Pedestal Mailboxes have discontinued these units. They will no longer manufacture these mailboxes in the U.S. as of 11/30/2020.

The 4C Pedestal mailbox is very similar to the CBU, except the 4C pedestal is not pre-approved by the USPS. These units will require USPS approval if used for USPS mail delivery and outgoing USPS pick-up. We strongly recommend that you contact your local postmaster for approval of the 4C Pedestal Mailbox before completing your purchase. Feel free to call and speak with one of our product experts if you need more information.

CBU Accessories and Related Products

We offer a wide selection of cluster box accessories and related products. Among the best-sellers, we offer the standard USPS Approved Parcel Locker. You can select from either a 2-Parcel unit or a 4-Parcel unit, and in one of six color options to match your selected unit. Although standard numbering will ship the fastest, custom numbering is available.

Cluster Mailboxes FAQ

📫Who is responsible for cluster mailboxes?

While the post office is responsible for installing and maintaining their proprietary Arrow Lock on the cluster mailbox master door, the purchase, installation, and maintenance of cluster mailboxes remain the customer's responsibility. If you are a property manager, you are responsible for cluster mailboxes. If you are a member of an HOA, please refer to your HOA's Covenants, Conditions & Restrictions document. Here's a good article with more info.

  • Responsibility: the USPS is responsible for installing and maintaining the Arrow lock. The CBU owner is responsible for the installation, maintenance, and preservation of the mailbox unit itself.
  • You, the CBU owner, are Accountable to install and maintain the cluster mailbox(es).
  • The USPS will install and maintain their proprietary Arrow lock mechanism for the master door.

📭How do cluster mailboxes work?

Cluster mailboxes (sold in our online mailbox retail store) are designed to provide secure mail access to multiple tenants from a centralized location. After the customer installs their CBU and sandstone pedestal, the USPS then installs their proprietary Arrow lock to access the entire unit via the master door. Parcel boxes (or parcel lockers) are accessed via a special key left in the tenant’s individual compartment by the postal carrier. Tenants can then retrieve their mail from individual compartments at their convenience. And that's it. For more details, view this article on how cluster mailboxes work.

Looking for a deal? Use a Budget Mailboxes Promo Code in checkout and save.

📬How does the post office access cluster mailboxes?

After the customer installs their cluster mailbox, the postal carrier then installs the USPS proprietary Arrow lock to access the entire unit via the master door.

Once you contact your local post office, the USPS or postal service carrier would schedule a time to service the CBU mailbox units and install the Arrow lock on site.

📮Are cluster mailboxes USPS approved?

Yes, all cluster mailboxes (or cluster box units) are pre-approved by the USPS for incoming and outgoing mail.

The US Postal Service prefers and in some cases requires that new residential developments purchase cluster mailboxes. For installation and maintenance topics, visit this article.

📪Who is the manufacturer of USPS approved cluster mailboxes?

Florence Manufacturing and Salsbury Industries are the two primary manufacturers of USPS approved cluster mailboxes in the United States. We carry CBU mailboxes by both manufacturers here at Budget Mailboxes. Note: Salsbury cluster mailboxes often ship faster.

Since there are only two main manufacturers of postal approved cluster box units in the United States, much of the supply chain is dependent on their mailbox inventory and production at the factory level. If you have questions about which types of cluster mailboxes are pre-approved for centralized mail delivery, contact your local post office.

📬What are Cluster Mailbox compartment sizes?

Cluster mailbox tenant compartments come in three sizes:

  • Standard, 3 in. H x 12 in. W x 15 in. D
  • Large, 4 - ¾ in. H x 12 in. W x 15 in. D
  • Extra Large, 6 - ½ in. H x 12 in. W x 15 in. D

Note: the tenant compartment size directly corresponds to the number of tenant doors available. Standard compartment sizes come in 8, 12, and 16-tenant configurations, while the large compartment size comes in a 13-tenant-door configuration. Finally, the extra-large compartment size is only available in a 4-tenant-door configuration.

For USPS mailboxes and clusters, the standard and large sized tenant box both accommodate most types of daily mail.

What to Know About Neighborhood Cluster Mailboxes

Newer neighborhoods and residential developments often utilize CBU mailbox installations at centralized locations. Cluster box units are convenient for the USPS and save the postal carrier time. Rather than having to deliver mail to each of your neighbors, the postal carrier delivers mail to a central location. To check your tenant boxes may require a short walk from your house to the centralized location, or you can pick up your mail from the cluster box mailboxes on your way in or out of the neighborhood.

Shopping for neighborhood mailbox clusters? Salsbury cluster mailboxes ship fast.

Five Year Warranty

Every cluster mailbox we sell comes with a Five (5) Year Warranty.

Florence Manufacturing provides a five (5) year Warranty on its products from the date of purchase from an Authorized Florence Dealer.

Likewise, Salsbury Industries covers defects in material and workmanship if reported in writing to them within five (5) years of the delivery date for any cluster mailbox.

5 Year Commercial Cluster Mailbox Warranty

Wide Tenant Boxes Accommodate Larger Envelopes and Magazines

tenant compartments for cluster mailboxes

Shown above: the 16 Door CBU Tenant Box (3 in. high)

wide tenant compartment cluster mailbox

Shown above: the 13 Door CBU Tenant Box (4 - ¾ in. high)

The CBU tenant compartment size is the current USPS Standard for centralized mail delivery. Under 4C regulations, the tenant boxes are wider so that all mail, including larger envelopes and magazines, can be delivered flat without any folding. There is also enough room in each tenant box for small-sized parcels.

What is included with the CBU?

What is included with the CBU?

The CBU cabinet and pedestal are packaged separately. Below is a list of components and hardware you will receive in each CBU’s package.

Pedestal shipping box includes:

  • Template guide to locate the pedestal base anchors.
  • Rubber Pad to be installed between the ground and the pedestal base.
  • The Pedestal, fully assembled.

Cabinet shipping box includes:

  • Cluster mailbox and integrated parcel lockers.
  • Hardware kit in plastic bag (shipped inside the CBU compartment) that includes:
    • Pedestal hardware.
    • Tenant door keys.
    • Parcel keys and tags.
    • Installation manual.
  • Cleaning instructions.
  • Parcel door hardware (in a plastic bag inside the cabinet). This includes two (2) McGard screws and three (3) two-way screws, four (4) Arrow Lock nuts, and panel lock covers attached with temporary plastic fastener.

Need more info? Check out the video overview below.

Customer Questions & Answers

Question: Are there illuminated mailboxes in large cluster box design?
Answer: The outdoor solar lamp from Whitehall may be the closest outdoor lighting solution we have to fit what you describe. However, if you are purchasing new cluster mailboxes, these stucco mail centers with solar lamp toppers.

Question: Do high-security cluster mailboxes come with private locks?
Answer: Yes, you can configure high-security cluster mailboxes with optional private locks, or you can purchase the conversion kit for your existing units.

Question: Do cluster mailboxes come with the needed hardware to mount to the ground?
Answer: While we do not include them by default, you can purchase four expansion or L-bolts with your CBU mailbox. Just select the bolts you need from the options menu.

Question: Is there a wireless alert system to know if the USPS has delivered mail has to my CBU? I live six streets from our cluster mailbox location.
Answer: While such a feature is not available for the Cluster Mailbox itself, you can register online with the USPS for Informed Mail Delivery to receive email notifications with snapshots of your mail every time the postal carrier completes a delivery.

Question: We have 120 tenant boxes in cluster style mailboxes and would like to cover them with a roof to protect customers and mail from direct rain. Do you represent or recommend any such covers?
Answer: Yes, the best solution we have is the outdoor Postal Kiosk by Vixen Hill. It is a prefabricated kiosk designed to house multiple units.

Question: Do you sell replacement locks?
Answer: Yes, we do. Let us know who the manufacturer of your cluster mailbox is, and we will provide you with the exact item.

Question: Where can I find the hinge pins to install a CBU master door?
Answer: We sell the long hinge rod for Type III and Type IV mailboxes. However, they are specific to each manufacturer. You will need to verify who your mailbox manufacturer first.

Question: I am looking for a 10-door CBU unit. Do you have one?
Answer: The USPS Cluster Box Units are only available in a 4, 8,12,13, and 16-door configuration. However, you may be able to get approval for a 10-tenant 4C pedestal mailbox. Give us a call if you need more info.

Question: Are the 29-door units USPS approved?
Answer: Because the 29 door unit is a 4C pedestal mailbox, it requires approval from your local USPS. Note: it is not ADA compliant and does not meet the 1:10 parcel locker to recipient compartment ratio, so please keep that in mind.

Question: Do you have a cluster mailbox with a doorbell for six units?
Answer: The only mailboxes that can be set up with a push-button doorbell are the 6 Tenant Vertical Apartment Style Mailboxes. However, these doorbell accessories are discontinued and no longer available for sale unless you find one used or with another vendor.

Question: How do I get new keys for my cluster mailbox?
Answer: You can either buy the key blanks and have them cut or you will need to buy new locks that will come with new keys. Give us a call for further guidance. We would be happy to help.

Question: How do you install the 3312R Regency CBU?
Answer: To start, you should already have a concrete pad location that meets USPS specifications. Once that is all set, please view our How to Install a Cluster Mailbox article. If you still have questions, please give us a call.

Question: Do you have a high-security cluster mailbox for 3 or 4 tenants? And can you supply one made of steel rather than aluminum? I have had three vandal break-ins.
Answer: The High-Security Cluster Box Units only come in configurations of 8, 12, 13, and 16 doors. However, we have a recessed mailbox that comes with four tenant doors. None of these mailboxes are made of steel, though they do include stainless steel hardware. Configure it as Free Standing if you do not intend to mount on a wall. Please call us if you need additional assistance.

Question: What is the largest cbu mailbox available?
Answer: The 16 Door with 2 Parcel Lockers and the 8 Door with 4 Parcel Lockers are the two largest USPS approved cluster mailboxes.

Question: Does the 16 tenant Salsbury CBU mailbox come with keys for each box?
Answer: Yes, all cluster mailboxes come with keys for each tenant box.

Customers Who Trusted Us With Their Projects

Major League Baseball
Harvard University
JP Morgan
U.S. Department of Defense
U.S. Department of State
USPS Approved
Balfour Beatty
Oregon Tech
Syracuse University