【Several sizes】: M3 * 8/12/16/20, M4 * 8/12/16/20, M5 * 8/12/16/20, a total of 250. In addition, we have a total of 250 nuts in the corresponding sizes. 【High quality material】: Made of 304 stainless steel, with high strength, good resistance to rust and corrosion and long life. 【Precision design】: The screw complies with the standard metric system. The surface of the screw is smooth and no burr, the thread is clear and firm, easy to recesse and difficult to loosen. 【widely used】: The hex bolt is a kind of hex bolt. The main purpose of nuts and bolts is to fix; Are very useful for almost all craftsmen and even the handymen. They are also suitable for various areas such as the construction industry. 【Storage classified]】: All parts are classified and placed in different grids for easy access and storage to avoid confusion and loss. Features: 500 pieces in 4 sizes, diameter of Thread: M3 M4 M5, Length: 8 mm 12 mm 16 mm 20 mm, nut size: M3 M4 M5. Made of 304 stainless steel, it does not