Specifications:Material: Stainless steelType: Flat washerStandard: Imperial standardSize & Quantity:1/4, 10pcs3/8, 10pcs5/16, 10pcs4-40, 20pcs6-32, 20pcs8-32, 20pcs10-32, 20pcsWeight: 127g / 4.5oz(approx.) Features: Made of high quality steel material, these flat washers are sturdy and has long service. Flat washers can spread a load, and prevent damage to the surface being fixed, and insulate steel screws from surface. They can be used as a spacer, wear pad, pre-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 in this set. Each set includes many flat washers that can be used for a long time, so you don't have to run to hardware store looking for washers for quite a while.