Salsbury Industries 3504ZSU Surface Mounted Vertical Mailbox with USPS Access and 4 Doors, Bronze Manufactured by Salsbury Industries to USPS-STD-4B+ Specifications Individual compartment size is 5-1/2" W x 16-1/4" H x 6-3/4" D Doors include a 5 pin cylinder cam lock (with 2 keys)