CT Johnson Enterprises (TCL3-YL) Deadbolt Blockhead Trailer Coupler Lock Deadbolt Blockhead Trailer Coupler Lock For 2 inch and 2-5/16 inch Couplers Strong Tough Simple Hi-tech materials redefine the traditional lip engaging coupler lock, Durable, exterior grade powder coat finish, Double-sided automotive style key makes for easy insertion and removal Shuttered key opening prevents clogging and freezing