These service carts 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 2 or 3 welded shelves. The shelves have a 3 inch lip on them to keep the parts on the shelves. The cart can hold up to a 2,000 lbs load.