These imported "C" clamps are made of cast steel, heat treated for strength and durability with precisely aligned anvil and base tip for firm hold.  Heavy duty beaded construction, sliding T-Handle, heavy duty screw shafts.  Enameled paint and plated screw with heavy duty swivel base tip designed for professional use.  Each set contains one each 3", 4", 6" and 8" "C" clamp. These clamps meet U.S. Federal Specifications #GGG-C-406D.