USS, United States Standard, washers are designed to meet the majority of industrial applications in manufacturing, maintenance and repair. These Extra-Heavy flat washers are thicker than standard flat washers. The extra thickness offers more strength allowing them to be used in more demanding applications.

Fender washers are flat washers that have a large outer diameter in proportion to its central hole. This allows the washer more surface area to spread the load on wood or lighter gauge sheet metal.18-8 grade stainless steel refers to stainless steel with chromium and nickel content measured in percentages. That means that an 18-8 grade fastener has 18% chromium and 8% nickel content.