2-3 USPS-Approved Mailbox Equipment Mailboxes used in new construction projects can be one of the following two types of centralized mailbox equipment: Pedestal-mounted USPS-approved CBU. Wall-mounted USPS-approved STD-4C mailboxes (4C). The Postal Service annually publishes a list of USPS-approved mailbox equipment and approved manufacturers in its Postal Bulletin. http://about.usps.com/postal-bulletin/2017/pb22467/html/welcome.htm You can also find the latest list of USPS-approved equipment and approved manufacturers at: http://about.usps.com/what-we-are-doing/current-initiatives/delivery-growth-management/welcome.htm