NOTICE: Please consult your local postmaster for approval before purchasing and installing a new 4B+ Horizontal mailbox. Not all United States Postal Service-approved mailboxes are approved for all USPS applications.

USPS Approved 4B Horizontal Mailboxes

What are 4B Horizontal Mailboxes?

4B Horizontal Mailboxes are only allowed to be used as replacement commercial mailboxes.
Available in several configurations for new construction or replacement of existing mailboxes.
USPS 4B Mailbox is for private use only, meaning new construction or replacement of existing mailboxes. For new construction, you must use USPS-approved commercial mailboxes to ensure delivery and security.
4B Horizontal Mailboxes are secure and efficient.

Horizontal Mailbox Benefits

Horizontal mailboxes are secure mail delivery and office and private mail delivery.
Space saving design and can be installed in a secure mail room where mail carriers can retrieve outgoing mail from recessed units.
Commercial and non-commercial use, focus on a secure and reliable mail solution.
USPS and private delivery.
Designed for your personal mail needs and USPS approved.
Horizontal suite height is a key measurement for USPS approval and replacement.

Mailbox Selection and Design

4B horizontal units come in several standard door configurations.
Contact us to design a custom model, where you can specify door size, configuration and quantity to your needs.
Custom models are great for private delivery locations.
Custom models allow you to specify door size, configuration and quantity to your needs.
Clear plastic number slots can be added to the mailboxes for easy identification.
Rear loading mailboxes are for private use applications, such as office buildings or apartment complexes where deliveries can be managed by on-site staff or the USPS. You must obtain USPS approval when replacing existing mailbox installations in these locations.

4B Mailbox Features and Dimensions

4B mailboxes have stainless steel doors and locks.
Each 4B door is 3” x 12” x 15” with a drop-off slot for outgoing packages.
Front-loading mailboxes require 2 keys for access, more secure than rear-loading wall mounts.
Parcel lockers are for outdoor and indoor use.
Rear loading is for secure mail delivery.

Installation and Accessibility

Front-loading horizontal wall mailboxes have a master loading door for mail carriers to access all compartments at once.
Rear-loading wall-mount mailboxes have a door that opens from the back for secure mail delivery.
All wall-mounted mailboxes must be ADA compliant.
Front-loading horizontal mailboxes must be at least 28” above finished floor.

Compliance and Regulations

USPS no longer approves the 4B mailbox for new construction and only for replacement of existing 4B applications where USPS delivery is required.
If you plan to use the 4B horizontal for USPS delivery, contact your local postmaster to confirm approved use before ordering.
4B horizontal mailboxes must be weatherproof.