M3-M16 K nut k cap Nut. nut with flange head , zinc plated, carbon steel material . M3-M16 K nutMaterial:carbon steel ,stainless steel, etck cap Hex. nut with flange head , standard and non-standard , from M4-M40 , zinc , brass , nickel and so on for plating .Brand name:JCPopular washer with favourable price