Sizes - M2 x 8/12/16/20 mm - M3 x 8/12/16/20 mm - M4 x 8/12/16/20 mm - M5 x 8/12/16/20 mm - Screws come with matching hex nuts and flat washers - Different sizes meet various needs Material - 304 Stainless Steel - Good corrosion resistance in harsh environments such as high temperature, cold weather, and high humidity - Superior rust resistance and oxidation resistance for long term use Package - 1280 pieces total - Packed in a durable transparent box with label - Easy to identify sizes so you can select the right screw without buying separately Applications - Widely used in precision machinery, classified instruments, instruments, electronic products, printed projects, household appliances, communication products, locks, lamps, lights, toys, etc Practical uses - Electronics enclosures and DIY projects that require multiple screw sizes - Repair and maintenance of household appliances and lighting fixtures - Assembly and maintenance of small machinery and instruments