347 Stainless Steel Alloy is used for valve and valve housing.
High temperature silicone Nomex reinforced actuator diaphragm
17-7 PH Stainless Steel actuator spring gives consistent pressure at high temperature, resists "relaxing" at temperature to 900F (483C)
Nitronic 60 Stainless Steel is used for the valve seat, and valve bushing the same material used in the higher level gates for reliability and longevity