The following engineering specifications and standards are provided to the public to convey the U.S. Postal Service's requirements for various delivery and collection equipment.
These documents outline the design, testing and approval requirements which must be satisfied to be certified as APPROVED BY THE POSTMASTER GENERAL.

USPS-STD-4C - U.S. POSTAL SERVICE STANDARD WALL-MOUNTED CENTRALIZED MAIL RECEPTACLES  HTM | PDF

USPS-STD-7C - U.S. POSTAL SERVICE STANDARD MAILBOXES, CURBSIDE HTM | PDF