E.R. WAGNER Low-Profile Replacement Plate Casters are ideal for electronic and business machines, display stands, racks, and other items needing high-capacity and low height. Double row swivel construction. 3/8" diameter nut and bolt axle. Heat treated hardened and lubricated raceways. 2"Hx13/16"W and 2-1/2"Hx13/16"W casters are dual wheel style.Wheel type codes are:HR—hard rubberPH—phenolicPY—polyurethane