Material Copper Gasket Type O-Ring, Flat Exterior Finish Smooth Metal Type Copper Number of Pieces 200 About this item 【Outstanding Material】Our metal washers are made of high quality copper, which has good electrical conductivity, thermal conductivity, melting point 1083℃ and durable for daily use and can be used repeatedly. 【Easy to Use】The O-rings are very easy to install, the surface of the copper flat washer is smooth, reduces friction between fasteners, prevents leakage, insulates, prevents loosening or pressure leakage. 【Easy to Store】These copper flat washers are designed with a storage box, which makes the ring gaskets safer and more convenient to store, easy to carry and maintain good classification. This design will improve work efficiency. 【Wide Application】O-rings are perfect for water, sump plugs, fuel and plumbing fittings. The hydraulic seal kit is perfect for electrical connections on household appliances, appliances, automotive and marine. Ring washers are really