standard fastener 1.Technical : GB, DIN, ANSI ,BS 2.Material : spring steel 65Mn, stainless steel we specialize in all kinds of fasteners, washer, retaining ring , spring pin , other nonstandard fastener.Material : spring steel 65Mn HRC:40-50 Stainless steel : HV200Size:M4- M200 . Mostly keep a stock . We also follow custom required size. Regarding ISO9001:2000 .