Bolt-Hole Caster, 1/2 in Bolt Hole Dia., 1/2 in Mounting Bolt Dia., Steel Caster Frame Material, Zinc Plated Frame Finish, 300 to 999 lb Load Rating Range, 330 lb Load Rating, 1 Number of Wheels, Ball, 4 7/8 in Mounting Height, 3 7/8 in Wheel Dia., 1 3/8 in Wheel Width, Nylon Wheel/Tread Material, 70 Shore D Wheel/Tread Hardness, Hard, Yes Non-Marking