Features:Made of copper material, widely applicated for electrical connections on household and commercial appliances, automotive and marine uses in which the power source has a threaded/bolt-type connection.Geat replacement for old or broken flat washers. Smooth surface can reduce friction between the fasteners, preventing isolates,loosening and pressure.Highly screws, nuts and bolts of same sizes and feature solid bearing surface to prevent nut/bolt head from tearing through material. Specification:Material: CopperSize: M17 x 21mm x 1mm/0.67''x0.83''x0.04''(ID*OD*T)Package Content:20 x Copper Flat Washers.