... .ISO 9001:2008 certified 2.OEM manufacturer 3.+/-0.01mm tolerance 4.QC inspect after products finished 5.Steel A ... SS303, SS304, SS316 etc.2. Steel:Q235,20#,45# etc.3.Brass:C36000 ( C26800), C37700 ( HPb59), C38500( HPb58), ... C27200(CuZn37), C28000(CuZn40)4. Bronze: C51000, C52100, C54400, etc.5. Iron: 1213, ... as required metal mobile phone part for touch screen