Polyurethane Tread on Aluminum Core Wheel 600 lb Load Rating 300 to 999 lb Load Rating Range 4 in Wheel Dia 1 1/2 in Wheel Width Polyurethane Wheel/Tread Material Firm 92 Shore A Delrin Standard Tread Shape 3/4 in For Axle Size Not Included Includes Spanner Bushing Aluminum Wheel Core Material Yes Non-Marking 1 13/16 in Hub Length