【MATERIAL AND PACKAGE】: The hex socket machine screws and lock nuts are made of high quality 304 stainless steel with high strength, excellent anti-rust and anti-corrosion performance, which are durable. Besides, screws and nuts are packed in solid transparent box according to their size and type, which is convenient for users to store and fetch.【VALUE PACK】: You will receive 60 pieces of hex socket head cap screws, 60 pieces of stainless steel lock nuts, a total of 120 pieces. The sizes of hex socket head cap screws include : M3 * 12 (10pcs), M3 * 18 (10pcs), M3 * 25 (10pcs), M4 * 12 (10pcs), M4 * 20 (10pcs), M4 * 30 (10pcs). And the sizes of lock nuts include : M3 (30pcs), M4 (30pcs).【DELICATE DESIGN】: The lock nuts are attached with high-quality nylon washers, which can enhance the friction between internal and external threads, preventing loosening after installation. Therefore, the screws have good seismic performance.【INSTALLMENT】: The head of the inner hexagon screw adopts the special design of countersunk head. After installation, the head of the screw can sink into the working face, keeping the installation face smooth and the appearance of the workpiece flat and beautiful.【USED WIDELY】: The nuts and bolts commonly used in home, office supplies, machinery, construction, communication equipment, and creative DIY projects, is a good choice for machinery assembly and maintenance.