Trimax SXTM31(SXT3) 5/8" Receiver Lock & (SXTC1) 7/8" Span Coupler Keyed alike set includes one SXT3 5/8" Receiver Lock and one SXTC1 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 Premium 100% Stainless Steel construction Fits class III, IV and V receiver hitches