hard washer Materials:various are ok here Size:No.4-No.12 , 1/4"-1/2" Certification: ISO9001, ISO14001 Features: hard washer 1.StandardDIN137, DIN 6797. DIN6798, ANSI B 18.21.1,GBT9074 2.Material C1010-C1022, 65Mn, stainless steel A2, A4 grade, or other alloy steel as per your need. 3.Surface Finish plain, zinc plated of various colour, hot dip galvanized, nickel plated, dacromet and etc. 4. ...