Antimicrobial Polyurethane Tread on Plastic Core Wheel 550 lb Load Rating 300 to 999 lb Load Rating Range 4 in Wheel Dia 2 in Wheel Width Polyurethane Wheel/Tread Material Hard 50-60 Shore D Precision Ball Standard Tread Shape 1/2 in For Axle Size Not Included Includes Spanner Bushing Polyurethane Wheel Core Material Yes Non-Marking 2 3/16 in Hub Length