304 high quality stainless steel. Stainless steel is a common material with a density of 7.93 g / cm3, also known as 18/8. It has good workability and high toughness up to a temperature of about 800 degrees. Various screw sizes: M2 * 4 - M2 * 20, M3 * 4 - M3 * 30, M4 * 6 - M4 * 30, to meet different needs. It is a very essential manual tool for the family. With M2, M3 and M4 nuts and washers, installations are now more precise with an increased contact area, which reduces pressure and protects parts and screws. Nuts and washers are arranged in a storage box, so you can easily find your way around the sets and avoid loss when needed. They are anti-oxidizable and corrosive even at high temperature.The main use of stainless steel hexagon screw is very common in electronics, for electrical appliances, chemicals, water, machinery and equipment, furniture and many other areas. Features: Screw Size: M2 * 4 M2 * 6 M2 * 8 M2 * 12 M2 * 16 M2 * 20 M3 * 4 M3 * 8 M3 * 12 M3 * 16 M2 * 20 M3 * 30 M4