... Material: zinc alloy 2)Tolerance: +/- 0.005mm 3)Finish:Polishing , plating 4)Color:gray,white,black led ... 1)Material: zinc alloy2)Tolerance: +/- 0.005mm 3)Finish:Polishing , plating4)Color:gray,white,black,as ... ) Measuring & testing equipment: Projector , concentricity tester, hardness tester, roughness tester, torsion tester, tensile force tester,etc. 3 ) Materials: zinc alloy 4) Finish: Anodized ...