" High quality carbon steel.It has good workability and high toughness up to temperature of about 800 degrees.They have rust resistance and excellent oxidation resistance in bad environment such as the high temperature, cold weather, and high humidity areas, which can guarantee long time using. 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 temperatures. The main use of stainless steel hexagon screw is very common in electronics, electrical appliances, chemicals, water, machinery and equipment, furniture and many other fields."