Standard:DIN Material:stainless steel, steel, brass, aluminum, plastic Size:M1.6 M2 M2.5 M3 M3.5 M4 M5 M6 M8 M10, length range 4--50mm Finish:Blue zinc , black zinc , nickel plated, brass plated, passivation, etc Certificate:ISO9001:2008, SGS, Rohs Service:OEM Offerted