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 8 inches high x 2 inches wide swivel with brake and ridged polyurethane casters make maneuvering easy.//These models come with 5 welded shelves. The shelves have a 2 inch lip on 3 sides to keep the parts on the shelves. The cart can hold up to a 2,400 lbs load.