... name Electrical parts. Instructions for Electric-cable-screw.Hopper and double-alloy screw(screws,machine screw): 1.We are a ... screw: manufactured with high-quality nitro alloy steel, applying the method of hardening and tempering and nitriding, thus it enjoys the ... long working life, wear resistance, and anti corrosion. Besides, the technique of hard alloy spraying or chrome plating can be ...