RWM Casters Polyolefin Wheel, Roller Bearing, 500 lbs Capacity, 4" Wheel Dia, 2" Wheel Width, 2-7/16" Plate Length 1/2" Axle diameter, 2-7/16" hub length, 500lbs capacity Polyolefin wheels with straight roller bearing 65 to 70 Shore D durometer hardness Temperature range from -20 degree F to 230 degree F