... required. Always the barrettes are always double jacketed type or kammprofile type. . H Type Spiral Wound Gasket:Item no.: JSG - SWHSpiral ... SS304, 304L, SS316, SS316L, SS321, SS347, SS 410, Aluminium , Copper, Brass, Nickel 200, Monel 400, Inconel 600/625 ... pipe size or specific gasket dimensions2 -- Pressure rating3 -- winding and filler materials4 -- centering / outer ring or inner ring ...