• Flat copper washer kit made from high-quality copper, resistant and durable for prolonged use • Excellent electrical and thermal conductivity, with a melting point of up to 1083 ℃ • Smooth surface reduces friction between fasteners, prevents leaks, insulates, and avoids loosening or pressure leaks • Includes compartmentalized plastic storage box, easy to transport and maintain good organization • Ideal for sump plugs, water, fuel, and plumbing fittings • Suitable for car engines, marine engines, generators, and machinery • The kit contains 200 pieces in the following sizes: 30 x M5*9*1, 30 x M6*10*1, 20 x M6*12*1, 20 x M8*12*1, 20 x M8*14*1, 20 x M10*14*1, 20 x M12*16*1, 20 x M12*18*1.5, 20 x M14*18*1 • Includes storage box to keep washers organized and safe • Small parts, keep out of reach of children • Color may vary slightly due to lighting and screen conditions