... 3.strong making ability spiral wound gasket with inner ring and outer ring Spiral wound gasket with inner ring/centering ringThe spiral wound gasket is made of ... material: CS plated zinc, stainless steel as ss304 3316,AS31803, alloy, and so on.Spiral material:A3 ,OCr13, 1Cr13, 1Cr18, ... asbestos,non-asbestosStandard: ASME,ASNI,JIS, JPI, ISO, DN spiral wound gasket with inner ring and outer ring