... )Finish:Polishing , plating 4)Color:gray,white,black Lamp Base 1)Material: zinc alloy2)Tolerance: +/- 0.005mm 3)Finish:Polishing , plating4)Color ... , torsion tester, tensile force tester,etc. 3 ) Materials: zinc alloy 4) Finish: Anodized, Polishing, zinc plated , nickel plated , chrome ,etc. 5) Diameter ...