Salsbury 4C standard horizontal 3700 series mailboxes are USPS approved and meet the specifications of USPS-STD-4C. Ideal for apartments, residential communities, commercial buildings and many other applications, these units include one or two (2) front loading master door(s) that swing(s) on a continuous hinge. A compartment equivalent to two (2) 3-1/4″ high standard doors is used for outgoing mail collection. The compartment is labeled “Outgoing Mail” and includes a 10-3/4″ H x 3/4″ H mail slot and weather protection hood. The outgoing mail compartment includes the U.S.P.S. master lock access door and cannot be used for mail distribution. Fully integrated or stand-alone parcel lockers offer tenants a convenient way to receive packages on site. Units include factory installed 3/4″W x 1/4″ D trim and a solid rear cover. Custom engraved placards (related item #3767) are available as an option upon request.