A spiral wound gasket is an industrial kind of gasket manufactured to provide a strong, reliable seal in high-pressure, high-temperature, and corrosive environments. It represents mainly a metal strip wound together in some sort of spiral form, normally with stainless steel or another alloy. Between those metal layers, there are fills in the forms of graphite, PTFE, mica, or some othe... https://goodrichgasket.com/Spiral-Wound-Gaskets