1、Good electrical conductivity and thermal conductivity. 2、200pcs solid copper sump plug washer. 3、These Copper Flat Washers have better sealing effect by special process 4、All contained in a compact and transparent plastic case. 5、Great for sump plugs, water, fuel and hydraulic fittings. Features: Good electrical conductivity and thermal conductivity. 200pcs solid copper sump plug washer. These Copper Flat Washers have better sealing effect by special process All contained in a compact and transparent plastic case. Great for sump plugs, water, fuel and hydraulic fittings. Used in all types of engines ,including Car, Marine, Generators, Machinery and Plant. Specification: Material: Copper Size: M5*9*1, M6*10*1, M6*12*, M8*12*1, M8*14*1, M10*14*1, M12*16*1, M12*18* 1.5, M14*18*1 Weight: Approx.165g/ 5.8oz Package list: M5*9*1      30pcs M6*10*1    30pcs M6*12*1    20pcs M8*12*1    20pcs M8*14*1    20pcs M10*14*1   20pcs M12*16*1   20pcs M12*18* 1.5  20pcs M14*18*1    20pcs box              1pcs