4" X 1-1/4" Non-Marking Monotech (Donut) Rigid Caster, Partial Thread Guard, Loads Up To 260 lb 4 in, Wheel Width 1 1/4 in, Wheel/Tread Material Rubber, Wheel Core Material Polypropylene, Non-Marking Yes, Number of Wheels 1, Caster Brake Type No Brake Included, Tread Shape Donut.