Product Info Catalog Automotive Trailer & Towing Trailer Products Interlock Towing Starter Kit, Class II, 2.5-In. Interlock Towing Starter Kit, Class II, 2.5-In. Request a Quote UPC: 42899704317 SKU: 220600 Model Number: 7043100 2-1/2", Class II Interlock Towing Starter Kit, 7" Long, Fits 1-1/4" Hitch Box Opening, 2-1/2" Drop & 2" Rise, 2" Diameter Ball Size, 1/2" Pin & Clip, 3500 LB Capacity.