4B Horizontal Mailboxes

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More info about 4B Horizontal Mailboxes

Budget Mailboxes is proud to supply durable, secure 4B horizontal mailbox units in several configurations for replacement of your existing mailbox system.

Key notes about the USPS 4B Mailbox:

  • Due to a 2006 updated USPS ruling, the 4C is the current requirement for all new construction projects.
  • You may continue to use a 4B configuration after a renovation, provided the mailbox housing or wall opening does not change.
  • Our 4B horizontal mailboxes are available in multiple door sizes with various options of individual box quantities to fit your exact specifications.
  • Made of durable aluminum construction with stainless steel locks and hinges, these units are engineered to provide years of service.

Private use Applications

In most cases, 4B units have become designated ?private use only?, meaning they are approved for new construction only if the intended use is for a private organization such as office buildings, apartment complexes, colleges, etc.

However, if you plan to replace an existing 4B mailbox installation, these front or rear loading mailboxes allow delivery by the on-site staff (Private) or by the USPS (we strongly recommend getting USPS approval before replacing your existing units).

Collection units are also beneficial additions in private use applications. A letter collection unit is a centralized drop-box which allowing tenants to deposit outgoing mail in one secure location. You can purchase these individually or as accessories.

Private use Applications

Standard or Custom

Standard or Custom
Standard or Custom

4B horizontal units are offered in a number of standard door configurations. You may also contact us to design a custom model, which allows you to specify door size, configuration, and quantity according to your specific needs. The flexibility of various sizes and layouts for individual needs makes the custom models an excellent choice for private delivery locations.

Standard Features

  • Front loading
  • Recess-mounted
  • Prepared for USPS-installed Master Lock
  • Anodized aluminum finish (other finishes available as customization options)
  • 5-pin cylinder tenant cam lock with two keys (1,000 key changes)
  • Clear plastic number slots or engraved numbers
  • Snap-on outer trim kit (available by request)

Optional Features

  • Private master lock
  • 3 powder coat color finishes: aluminum, Dark Bronze, and Gold Speck
  • Combination lock (for private services only)
  • Configurable door sizes and layout options

How to choose between 4B and 4C mailboxes

As previously mentioned, the USPS mandates that the 4B mailbox is no longer acceptable for new construction. These mailboxes are available only as replacement units for existing 4B applications where USPS delivery is required. For a complete list of commercial mailboxes click here.

The 4C mailbox is the most current USPS standard for all new construction applications. If the opening dimensions for the cluster housing is modified in any way, then the 4B must be upgraded to a 4C CBU. If you intend to use the 4B horizontal for USPS delivery, then we encourage you to contact your local postmaster to verify authorized use before placing your order.

Note: 4B horizontal mailbox installations should be protected from direct exposure to the weather. The manufacturer is not responsible for damage caused by weather conditions as these products are rated for indoor use only.

If your project requires installing a 4C mailbox, please view our 4C horizontal category page. To view other commercial mailboxes, click here.

What is Standard USPS 4C?

The United States Postal Service expanded the width of mailbox compartments and answered the demand for more secure delivery with a new standard, USPS 4C. What does this mean?

  • This standard replaces the traditional, cube style compartments with more flat style compartments and incorporates integrated or stand-alone parcel locker options.
  • A minimum of one parcel locker is required for every ten tenant compartments.
  • Parcel lockers are not required in installation sites with less than ten tenant compartments.
  • This standard requires that 4C horizontal mailboxes and parcel lockers be installed in all new construction projects and major remodels effective October 2006.

What is Standard USPS 4B+?

The demand for improved mailbox security prompted the United States Postal Service to develop this standard. Some key notes to remember:

  • This standard requires manufacturers to strengthen and improve the master door (arrow lock compartment) on horizontal style mail receptacles.
  • Our 4B horizontal mailboxes are USPS approved and in full compliance with the requirements of USPS 4B+.
  • These 4B+ horizontal mailboxes are approved for replacement and/or retrofit installations effective October 2006.
  • For new construction or major remodels (if the housing dimensions are modified), 4C horizontal mailboxes are required.

Customer Questions & Answers

Question: what is the cost to install a cluster of mailboxes?
Answer: Sorry, but we don't offer a mailbox installation service.

Question: I'm looking for a front loading data distribution boxes with locks.
Answer: Please view our selection of  Data Distribution boxes for more details. Thank you.

Question: What are the door and compartment identification options for the 4B Horizontal mailbox?
Answer: Each mailbox door includes a 2'' W x 5/8'' H clear plastic card holder to identify the tenant's name and/or box number. Self-adhesive numbers (1-3000 available) are supplied upon request with a standard order. Custom identification systems are available as an option upon request. Label holders (#1070) neatly organize and identify the front/rear of the mailbox compartments and are available as an option upon request. Thank you for your inquiry.

Question: do you guys sell only doors? I'm missing 5 in my property, let me know.
Answer: Yes. If you can identify the specific mailbox you have, on the budgetmailboxes.com listing for that mailbbox, there is a section below the mailbox images for parts. You can find and purchase the mailbox door from there.

Question: Do you have a 16 horizontal mailbox with rear loading and private use only. Our current box is 28" wide, 23" deep and 23 1/2" high. There are 15 private boxes and the 16th box is for outgoing mail.
Answer: We carry a 15-door and an 18-door mailibox but do not have a 16-door mailbox available.

Question: Do you have an 8-bank mailbox available?
Answer: Yes, please view our 8-door horizontal mailboxes for more details.

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