High quality 304 stainless steel. Stainless steel is a common material with a density of 7.93 g/cm3, also called 18/8. It features good workability and high toughness up to a temperature of about 800 degrees. Various sizes of flat washers: M3 30 pcs, M4 30 pcs, M5 40 pcs, M6 35 pcs, M8 40 pcs, M10 40 pcs, M12 10 pcs, to meet different needs. It is a very essential manual tool for the family. Flat washers can be used in combination with screws and nuts. The flat washers increase the contact surface, reduce pressure and friction, and prevent the screws from coming loose. The flat washers are arranged in a storage box, which makes it easy for you to find them and prevents loss when needed. Application: Perfect for electrical connections on household and commercial appliances, automotive and marine uses in which the power source has a threaded or bolt-type connection.