Material:
Housing in aluminium.
Reflector in aluminium or white plastic.
Polyamide viewing lens.
Version:
Transparent viewing lens,
temperature-resistant with oil up to 100 °C, with water up to 70 °C.
Flat seal, asbestos-free.
Note:
The G3/8" and M18x1.5 versions have a white plastic reflector.
Drawing reference:
1) flat seal