C9100 & C9200 are the only mailbox locks approved by USPS for 4C (CBU) mailboxes.

USPS specification USPS-L-1172C for USPS-STD-4C mailboxes.

This Lock can withstand 1000 pounds of force applied to the cam.

Accommodates up to 3/16″ thick cam C7120

Drain holes on the bottom of the cylinder

APPLICATION Exterior pedestal-mounted neighborhood boxes. Has keyway dust shutter for lock protection. Clip mounted.

OPERATION C9200 operates counter-clockwise. Key removable in locked position only.

KEYING Available keyed differently only (2,000 changes).
Includes: a spring clip, mounting nut and (3) keys.