Rubber Wheel, 4″ diameter, 2-3/8″ x 3-5/8″ top plate, with top lock brake, 1/2″ king pin, non-marking, 250 lb. weight capacity, operational temp range -45° to 180°F, resistant to oil, grease, water &most solvents, double ball bearing, smooth and quiet, zinc plated, gray, NSF