MAP sensor o-ring material?

[Whitedemon]

Does anyone know the material of the green o-ring on our map sensors? Is it silicone? Rubber? Tried searching everywhere and can’t find it. Thanks in advance

 

[GTI's]

Mostly the green O-Rings are Highly Saturated Nitrile (also known as Hydrogenated Nitrile) and are commonly referred to as HNBR