1.quality flange nut 2. stanless steel or steel made Flange NutFlange nut made of carbon steel, stainless steel.Standard: DIN6923Dimension according to standard or customs designSize: M4, M5, M6, M8, M10, M12,M14,M16,M18,M20Inch size is also availableDifferent surface finish is available Clasee 6,8,10 flange nut,fasterner m5,m6,m8,m10,m12,m14,m16,m18