New style USPS postal mailbox lock manufactured by Compx/National. Lock rotation is 90 degrees counter-clockwise. Supplied without locking cam - supplied with parts shown. Each lock supplied with 3 working keys.
Normally, this lock works in applications when the door is hinged on the right. When in the locked position, key removal is vertical at 12:00, key rotates 90 degrees counterclockwise to unlock position. Key does not remove at unlock position.