The washer is a thin disk-shaped plate with a hole in the middle that is normally used to distribute the load of a threaded fastener, such as a screw or nut. Other uses are as a , wear pad, -load indicating device, locking device, and to reduce vibration. High-quality bolted joints require hardened steel to prevent the loss of -load after the is applied. are also important for preventing galvanic corrosion, particularly by insulating steel screws from aluminum surfaces.This flat are made of high quality copper of good electrical conductivity and thermal conductivity.Flat can spread a load, and prevent damage to the surface being fixed, and insulate steel screws from surface.Can be used as a , wear pad, -load indicating device, locking device, and to reduce vibration.Flat washer is applied when the hole is a larger diameter than the fixing nut. There are many different sizes of in this set from which you can use for different purposes.This set includes many flat that can be used for a long time, so you 't have to run to hardware looking for for quite a while.Material: CopperColor: copperType: Flat washerID*OD*Thickness -- :*9*1mm -- 30pcsM6*10*1mm -- 30pcsM6*12*1mm -- 20pcsM8*12*1mm -- 30pcsM10*14*1mm -- 30pcsM8*14*1mm -- 20pcsM12*16*1mm -- 25pcsM14*18*1mm -- 25pcsM12*18*1.5mm -- 20pcsM16*20*1.5mm -- 20pcsM16*22*1.5mm -- 15pcsM20*26*1.5mm -- 15pcsPackage Contents:280 x copper 1 x plastic boxOnly the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.