Our #20 Series casters featuring floor safe, non marking polyurethane tread wheels bonded to a polyolefin core. Poly wheels provide a lightweight and high capacity wheel option. Polyurethane resists flat spots on the tread from long periods of standing. This smooth rolling and quiet wheel is resistant to oil, grease, water, and most solvents. Wheel tread hardness of 90-95 Shore (A) Durometer. For more caster options, including bearings and top plates, please call our sales team in West Reading, PA, at 1-800-215-8220.