Insert Nut 1)Size:M3 to M12 2)Flat head, flat hexagon head,small countersunk head 3)Material:mild steel Rivet nuts 1.Material:stainless steel ... : UNC6-32~1/2-133..Finished: Zince, Nickel,etc.4.Flat head, flat hexagon head, small countersunk head5..Rivet Standard: DIN, JIS ,ISO, BS ...