RWM Casters DUR-0415-06 4" Diameter X 1-1/2" Width Durastan Phenolic Wheel with Straight Roller Bearing, 600 lbs Capacity, 3/8" Axle Diameter 3/8" Axle diameter, 1-7/8" hub length, 600lbs capacity Durastan phenolic wheel with straight roller bearing 90 Shore D durometer hardness Temperature range from -65 degree F to 275 degree F continuously, 300 degree F intermittently Lubrication fittings standard on 2-1/2" and wider wheels