Made of steel for lasting durability and strength. Moves up to 40 chairs at once allowing fast, easy break down of rooms. Two swivel and two fixed hard rubber casters allow safe and easy maneuvering of chair stacks. For use with Model B449423, B449424, B449432 & B449435 only. Size is 20-1/2" L x 21" W x 26" H. Color finish is Black.