The IPA Tractor Trailer / Truck 7 Round Pin Plug circuit Tester #7865L is a specialized tool designed for testing electrical connections in tractor trailers and trucks. Made by IPA, a trusted brand in the industry, this tester features a 7-round pin plug design and a manufacturer part number of 7865L. It is specifically designed for use in diagnosing electrical issues in these types of vehicles, making it a valuable asset for automotive mechanics and repair technicians.