The CompX National C8718 is a bright-nickel finished, 5-pin tumbler mailbox lock engineered specifically for architectural mailboxes serviced by the USPS. It features a 90° counter-clockwise cam rotation with the key removable only in the locked position, ensuring secure access control. Supplied keyed differently out of the box—with two keys and a spring mounting clip included—it installs in a standard 0.635" × 0.760" mounting hole using a simple spring clip, providing an effective and easy replacement for aging Cutler Mail Chute locks.