Product description Packing content: 684 pieces countersunk screws 1.304 high quality stainless steel. Stainless steel is a common material with a density of 7.93 g/cm3, also known as 18/8. It shows good workability and high toughness up to a temperature of around 800 degrees. 2. Different sizes plate washer: M2 120PCS, M2.5 120PCS, M3 120PCS, M4 120PCS, M5 70PCS, M6 50PCS, M8 50PCS, M10 22PCS, M12 12PCS, to meet different family needs. 3. For plate washers, the spring washer is used under the nut to prevent the nut from loosening. Washers are used for loosening, washers have no loosening function, and washers only increase the contact area. 4. The washers are arranged in a storage box, easy for you to sort through the sets and avoid losing when needed. 5. Application: Perfect for electrical connections on home and commercial appliances, automotive and marine applications where the power source has a threaded/bolt connection.