DIN/ASTM flange nut 1.carbon steel,alloy,al,cu,SS,etc 2.zinc,black,HDG.etc. 3.also as the customer need. DIN/ASTM flange nut1.carbon steel,alloy,al,cu,SS,etc2.zinc,black,HDG.etc.3.also as the customer need.All kinds of nuts Class: 6/8/10 Gr.2/5/8 Material: Steel/Stainless Steel/Brass Surface treatment: zinc plated, black, H.D.G flange nut