... 3.+/-0.01mm tolerance 4.QC inspect after products finished 5.brass A:certification: ISO9001:2008B.Products Available bolts, screws, nuts, ... , 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, 12L14,1215 etc.6. Aluminum: Al6061, Al6063,AL7075 ...