These are our service carts that make mobility of heavy machine parts and tools and dies from shop to assembly areas easy. Uprights are made from 2 inch by 2 inch x.25 inch angle with 12 gauge heavy duty shelves. A handle is provided for steering. The sturdy 6 inches high x 2 inches wide swivel with brake and ridged polyurethane casters make maneuvering easy.//These models come with 3 welded shelves. The top shelf is punched for CAT 40 or CAT 50 dies and the middle shelf is angled and also punched for CAT 40 or CAT 50 dies. The bottom shelf has a 3 inch lip on them to keep the parts on the shelves. There are also 2 vise shelves on the cart to work from.