Made of 304 stainless steel, durable, corrosion resistant, high hardness 7 Common Sizes for general use, including: M3, M4, M5, M6 , M8, M10, M12;general purpose use, ideal for professionals and hobbyists Nylon insert lock nut features an integrated nylon system that grips bolts to prevent loosening Nylon collar can prevent bolts from coming out for a more secure and durable grip Specification: Material: 304 stainless steel Size Thread Size: M3, M4, M5, M6, M8, M10, M12 Weight: 430g Color: Silver Package Content 45Pcs Lock Nut x M3 35Pcs Lock Nut x M4 30Pcs Lock Nut x M5 25Pcs Lock Nut x M6 15Pcs Lock Nut x M8 10Pcs Lock Nut x M10 5Pcs Lock Nut x M12