flange insulating gasket kits have main 3 types. Type E for FF flange, type F for raised face flange and type D gasket for RTJ flange

A flange insulation kit consists of a flange gasket, bolts and insulating sleeves used to install a leak-proof flange. The insulating sleeves used in the kit are manufactured of a high-density, polyethylene plastic that prevents an electrical charge from dissimilar metals from causing corrosion and ......

A concave PTFE Inside Diameter (ID) seal and a PTFE spring-energized face seal, or an elastomeric O-ring, seated in an insulating laminate and permanently bonded to a high-strength core