DESCRIPTION - Black Luster® Grade 8 Steel USS Washers provide best in class decorative appearance and better corrosion resistance than black oxide and zinc plated finishes. Resistant to 1,000 hours of salt spray per ASTM B117*. Washers are primarily used to displace the load of a fastener head or a nut on a threaded joint. They can cover holes and act as spacers. These washers meet United States Standard specifications. & generally have a larger ID and OD than SAE washers. These washers should be used whenever high-strength hardened steel bolts specify the use of High Strength Grade 8 Washers.