As the name indicates, CURT A-frame couplers are meant to mount onto A-frame trailers. An A-frame trailer is one with a frame that meets in an A shape at the front end. CURT A-frame couplers are stronger than standard couplers, making them especially common for RV trailers. We have three options of A-frame couplers available, including Posi-Lock, easy-lock and sleeve-lock styles. CURT A-frame couplers range in towing capacity from 5,000 lbs. to 12,500 lbs. and have ball diameters of either 2” or 2 5/16”.