Trimax TM31 (T3) 5/8" Receiver Lock & (TC1) 7/8" Span Coupler Lock Keyed alike set includes one T3 5/8" Receiver Lock and one TC1 7/8" Coupler Type A key which is a spring loaded, 7 pin, high security key. Resists attempted drill outs. Rugged and durable, the key will not bend or break. Lifetime Warranty Chrome finish Fits class III, IV and V receiver hitches