... steel,brass,aluminum.etc. 5.can be custo Ring Metal Gasket:1. Materials:Different kinds of stainless steel, (303,304, 316 ... Etc) Brass ( C3602, C3604, lead-free, Etc) , aluminum( 6061,6063 Etc.) , steel, etc.2. Diameter size ... please tell me! Don't hesitate to contact me! Metal gasket