1. This set of flat washers is made of high-quality copper with good electrical and thermal conductivity. 2. Flat washers can distribute a load and prevent damage to the surface to be fastened and insulate steel screws from the surface. 3. Can be used as a spacer, wear pad, preload indicator device, locking device, and to reduce vibration. 4. The flat washer is applied when the hole has a larger diameter than the fastening nut. There are many different sizes of washers in this set that you can use for different purposes. 5. This set includes many flat washers that can be used for a long time, so you don't need to run to the hardware store looking for washers for a while.