The new FID46 is based on a heavy gauge 3inch round stock steel mainframe, with a 9-position seat and back pads that are a full 2¾inch thick and will never bottom out. Perfect for all types of barbell and dumbbell exercises, the FID46 works great in Power Racks, Smith Machines and the strongest leverage gym system in existence. In addition to all the intense upper body exercises the FID46 delivers, the leg developer provides a concentrated lower body workout. Perform leg extensions with full 90 degree seat back support and lying leg curls from the traditional arched prone position. Specifically designed for use with the SBL460. Olympic style plates only. Weight plates and collar optional.