Steel top plate and inner raceway of Endurance Series are formed from one piece. Raceway is CNC machined and induction hardened, providing better stability than standard steel-to-steel plate welding. Kingpinless style caster is designed for 2 and 3 in. wide wheels for capacities up to 3,000 lb; Super Endurance Series handles up to 5,000 lb. Caster is finished in zinc plating and comes standard with 6 wheel types.