TowSmart ProClass Heavy Duty Coupler Lock 9006 - The Home Depot
Amazon.com: SKARUMMER 2Pcs Trailer Hitch Locks, Tongue Coupler Lock with Keys, Diameter 1/4 Inch, 3/4 Inch Span Coupler Locking Pin for Tow Trailer RV Truck Car Boat, Alloy Metal Black : Automotive