The Trimax SXTM3123 Universal Receiver Coupler Lock Set includes a Receiver Lock with 1/2" pin to fit all class II receiver hitches and a 5/8" adjustable sleeve to fit Class III, IV, and V receiver hitches. This set also comes with a Coupler Lock that adjusts to fit couplers with 7/8", 2-1/2", and 3-1/2" span. Constructed with machine-forged stainless steel, these locks feature internal O-ring and weather-resistant rubber cap to help keep water, grime, and dirt out of the locking mechanism. This lock set comes with four keyed-alike round keys that won't bend or break.• 1/2" pin fits Class II receiver hitches>br/>• 5/8" adjustable sleeve fits Class III, IV, and V receiver hitches• Fits 2-3/4" span• 1/4" dia. pin adjusts to fit couplers with 7/8", 2-1/2", and 3-1/2" span• Made of stainless steel• Internal O-ring and watertight cap to seal out moisture• 1/4 turn locks and unlocks head• Lock head can't be false locked or pop open• Includes 4 keyed-alike round keys Internal O-ring & watertight cap seal out moisture Made of 100% stainless steel Includes 4 keyed-alike round keys with easy 1/4 turn lock & unlock | Trimax Universal Keyed-Alike Receiver Coupler Lock Set, 1/2" - 5/8" x 2-3/4" Receiver and 7/8" - 3-1/2" Span Coupler