The CURT tri-ball universal coupler lock offers superior security for your trailer and towing setup. The unique triple ball insert and lasso lock can be used while the trailer is hooked up to the hitch or when it is parked and left unattended. The tri-ball is made from glass-filled polymer, a highly durable material, and it fits standard couplers, including 1-7/8-inch, 2-inch and 2-5/16-inch.