Heavy-duty plastic truck will not rust, discolor, or warp. Maintenance free and easy to clean. Honeycomb construction is reinforced for longer life. Extra square steel tube underneath platform to reinforce deck strength. Units roll smoothly on 6" x 2" polyurethane casters. The four wheel cart has two rigid and two swivel casters, while the 6 wheel cart has 4 swivel and two rigid casters. Handle height 34".