Countersunk head blue nylok machine screw; Stainess steel, etc. Anti-loose nylok; Used on machinery etc RoHS compliant. Phiilips Countersunk head nylok screw:Item name: nylok screw; Material: stainless steel,iron,carbon steel,aluminum,brass,copper;Surface Treatment: natural,zinc plated,chorme plated,nickel plated,brass plated with nylok;Head Type: pan head,truss head,bind head,flat head,oval head ...