We carry three main types of 4C mailboxes, including: Pedestal Mount 4C Mailboxes: designed for use outdoors where mailboxes are installed on a pedestal stand. Front Loading Surface Mount 4C Mailboxes: designed for indoor use and installed on the wall surface. Rear Loading Recessed 4C Mailboxes: designed for indoor use and installed into an opening within a wall with rear access from a private locked room.