Antimicrobial Nonmarking Rubber Tread on Plastic Core Wheel, 325 lb Load Rating, 300 to 999 lb Load Rating Range, 4 in Wheel Dia., 1 1/4 in Wheel Width, Thermoplastic Rubber Wheel/Tread Material, Firm, 85-95 Shore A, Precision Ball, Donut Tread Shape, 7/16 in For Axle Size, Not Included Includes Spanner Bushing, Plastic Wheel Core Material, Yes Non-Marking, 1 9/16 in Hub Length