Energy-saving wrench (double blister) 1 Stainless steel wrench 2 Precision double ... customized designs by materials of stainless steel, mild steel, aluminum, copper, brass, bronze, etc.Surface treatment: zinc/nickel/chrome plating, hot ... treatments.5) +/-0.001 mm tolerance will be controlled. 5PC energy-saving wrench (double blister), precision machining parts, stainless steel machining parts ...