Stanley Proto J1221M-T500 Combination Wrench 21mm ASD Fully Polished 12 Point,Stanley Proto,J1221M-T500" /> Special heat-treated alloy steel permits slim shanks for strength and durability. Box ends incorporate the TorquePlus system Ideal for use on stubborn or damaged fasteners helps to extend fastener life, and allows the user to more easily turn worn, rounded, or rusted fasteners. Corrosion resistant and easy to clean surfaces.