... washers SpecificationM2-M40MaterialMild carbon steel, medium carbon steel, high carbon steel, Stainless steel,copper,phosphorization, dacromet,cuprodine. ... ISO,GB,DIN,JIS,ANSICetificate ISO9001-2008,SGS,ROHS Function Aatomobile,electronic,mechinery After sale serviceIf there ... for it. superiority Good quality,free for samples.Product photos for referenceFlat washers Spring washersOther type of washers ...