GN7 - 4" square tube with kingpin. Pull your gooseneck trailer with a semi-tractor or pickup mounted fifth wheel. Simply replace the coupler with a king pin. Easily switch back and forth. 2? SAE king pins are the industry standard and are suitable for use in all over-the-road applications. 30,000 GWR, powder coated finish, 10" round bolster plate. 4In Square Gooseneck Trailer W/5Th Wheel Truck Adaptor 30,000 Lbs Rating Powder Coat Finish 10" Round Bolster Plate MODEL NO - GN7