This low-profile hex nut is made from bright steel, meaning the material hasn't been coated or given any surface treatment. It's manufactured to ISO 4035 standards and features a metric thread. Rated at strength class 5, it's commonly paired with class 5.6 or 5.8 fasteners in pressure vessel applications. Keep in mind that bright steel offers little to no built-in corrosion resistance, so that's something to factor in when putting it to use.