Type D gaskets are specifically designed to fit into the ring groove of ring-type-joint flanges. They are manufactured of a medium weave, fabric-reinforced phenolic material and are sized to ANSI specifications available in basic oval as well as octagonal shape. also available are BX gaskets with pressure ratings to 15,000 PSI.
G10 / G11 withViton / Spring Energized Gaskets

We use a machined glass-reinforced epoxy (Gre) resin with an o-ring or spring energised seal to produce this insulation set. It can be used for flange ratings from class 150 to 600 and offers greatly improved compressive strength over conventional insulation sets with greater resistance to over compression and cracking.
Metal Core With G10 / G11 Gaskets

These gaskets are high reliability gasket used
for both insulating and general sealing purposes
in Very Critical Services. the gasket has a proven
track record of integrity in aggressive sealing
situations. It is suitable in all services up to and
including anise 2500# and API15,000# classes.
This gasket consists of a PTFE(Teflon) spring energized face seal, or an elastomeric O-ring,
seated in an insulating laminate, which is
permanently bonded to a high-strength metal
gasket core.
Due to its unique pressure activated sealing
mechanism, the gasket requires far less bolt
stress to seal than any other gasket. Gasket inner
diameter is exactly matched to the flange bore
to eliminate turbulent flow and flange face
erosion/corrosion. the seal elements are
replaceable in the reusable gasket retainer.