These hex nuts are made from 18-8 stainless steel, which is characterized as having a chromium content of 18% and nickel content of 8 to 10%. Designed for use with stainless steel bolts and screws with a specified minimum tensile strength equal to or less than the specified proof stress of the mating nut. The primary property of this nut is its corrosive resistance. Common applications include: auto trim and molding, kitchen equipment, wheel covers, truck bodies, storage tanks, pressure piping and vessels, and boating. SSHN12C188