Postal service boxes with custom print file
Letter box (in the US usually called mailbox), positioned near or on the mail recipient's home or place of work.
Post office box, (often abbreviated P.O. box or PO box), a box rented by the mail recipient to be an independent postal address, located in a post office or in the premises of a company offering such facilities. Self-service boxes are unlocked by the recipient, otherwise a postal clerk retrieves the mail.
A relay box is similar to a post or mail box, but totally locked; post office trucks deposit mail that is then retrieved and delivered by pedestrian mail carriers. In the United States, they are painted differently from collection boxes.