High quality carbon steel.It has a good maneuverability and high tenacity up to a temperature of about 800 degrees. They have rust resistance and excellent oxidation resistance in poor environment such as high temperature, cold weather, and high moisture areas, which can guarantee a long time using. Different screw sizes: M2 * 8, M2 * 12, M2 * 16, M2 * 20, M3 * 8, M3 * 12, M3 * 16, M3 * 20, M4 * 8, M4 * 12, M4 * 16, M4 * 20, M5 * 8, M5 * 12, M5 * 16, M5 * 20, to meet the different needs. It is a very essential manual tool for the family. With the nuts and washers M2, M3 and M4, the installations are now more precise with an increase in the contact surface, which reduces the Pressure and protects parts and screws. The nuts and washers are arranged in a storage box, which allows you to easily find yourself in the series and avoid the loss when needed. They are anti-oxidizable and corrosive even at high temperature. The main use of the stainless steel hex screw is very frequent