High quality carbon steel. It has good processing and high strength up to a temperature of about 800 degrees. They have rust resistance and excellent oxidation resistance in bad environment like high temperature, cold weather and high humidity areas which can guarantee a long time. Different screw sizes: M2 * 4 - M2 * 20, M3 * 4 - M3 * 30, M4 * 6 - M4 * 30, to meet different needs. It is a very important manual tool for the family. With M2, M3 and M4 nuts and washers, installations are now more precise and the contact area increases, which reduces pressure and protects parts and screws. The nuts and washers are arranged in a storage box, which allows you to easily find in the series and avoid loss when needed. They are also antioxidable and corrosive at high temperatures. The main use of stainless steel hexagon screw is very often used in electronics, for electrical appliances, chemicals, water, machinery and equipment, furniture and many other fields. Dimensions: Material: Carbon