Mild steel slabs are relatively thin rectangular blocks of steel, weighing up to 20 tons per piece. A popular size can be 6500mm x 1200mm x 250mm with a specific gravity of 7.85; such a slab weighs 15.3 tons. Steel slabs are the basic material from which most steel products are manufactured. Slabs are usually stored in the open - unusually: for steel products, wetness and rust staining is of no consequence.