This SAE Standard includes couplings, hitches, and safety chains used in conjunction with all types of trailers or towed vehicles whose Gross Vehicle Weight Rating (GVWR) does not exceed 4540 kg (10 000 lb). This includes such types as utility, boat, camping, travel, and special purpose trailers which are normally towed by conventional passenger cars, light-duty commercial vehicles, light trucks, and multipurpose passenger vehicles. This document is intended primarily for ball-and-socket type of couplings and hitches. It should not be construed as a limitation to this type alone but should apply where appropriate to ring-and-pintle, clevis-and-pin, or any other draft means designed to serve this purpose.
J684 has been reaffirmed to comply with the SAE five-year review policy.