About This Article. Material: Copper, These Washers Are 100% Solid Copper. Brass Vein Flat Brass Are The Highest Quality Out There, Melting Point Up To 1083 . Types Of Size: Quantity: 150Pcs, Different Sizes Flat Washer M5, M6, M7, M8, M10, M10. 5, M11, M14, M12, M12. 5, M14, M15, M16, M16. 5, M17. 5 All Contained In A Plastic Box Compact Plastic And Glass. Washers Are Used With Nuts And Bolts, And Provide A Greater Bearing Surface To Prevent The Nut Or Bolt Head From Tearing Through Attached Hardware. The Flat Washers Are Arranged In A Storage Box, Which Allows You To Easily Find Yourself In The Series And Avoid Loss If Necessary. Good Electrical Conductivity And Thermal Conductivity. Ideal For Sump Plugs, Water, Fuel And Hydraulic Fittings. A Sump Intake Washer Is Suitable For All Types Of Engines Such As Car, Marine, Generators, Machinery And Factories.