What do different drop slots do in the USPS office?

What do different drop slots do in the USPS office? mailbox drop slot Versatile Front Loading Double Column Commercial Mailbox with 19 Tenant Doors and Outgoing Mail Slot Outgoing drop-boxes or mail slots will supply a safe and mailbox door slot adjustable-through-the-wall-mail-drop-slot This Mail

mailbox door slot drop - bottom letter box , MAIL LETTERS New Type of Drop

mailbox with slot and lock If you're interested in an easy way to ship mail, then dropping a package or letter in the mail drop slot is one of the easiest ways to do so They are the Keep your items dry and protected with our big rain proof door mail slot! The Rainproof Heavy Duty Mailbox Door Drop Box by POCHAR LLC is a sturdy and