Product material: copper. Contents: 1 set. Product size: single diameter from 0.9 to 1.3cm. Length and width of the box: 13 x 6.5 x 2.3 cm. Color: as the picture. Product Features: The flat washers are made of high quality copper, durable and rustproof, which has good conductivity. electrical and conductivity thermal. Flat washers can distribute a load, and prevent surface damage. fasten, and isolate the steel screws from the surface. Wide application, perfect for electrical connections on household and commercial appliances, automotive and marine applications. 9 sizes: (inner diameter x outer diameter x thickness). M5 x 9 x 1 mm 30 pieces. M6 x 10 x 1 mm, 30 pieces. M6 x 12 x 1 mm 20 pcs. M8 x 12 x 1 mm 20 pcs. M8 x 14 x 1 mm 20 pcs. M10 x 14 x 1 mm 20 pcs. M12 x 16 x 1 mm 20 pieces. M12 x 18 x 1.5 mm 20 pcs. M14 x 18 x 1 mm 20 pcs. Contents: 200 copper washers. 1 storage case.