Why are Injector O-Rings different colours?

�� Why are Injector O-Rings different colours?
�� Colors and their applications:
�� Blue:
High resistance to temperatures and chemicals.
Ideal for aggressive fuels (ethanol, gasoline added).
�� Verde:
General use in gasoline systems.
It offers good elasticity and flexibility.
Mar Brown (Viton):
High resistance to extreme temperatures.
Recommended for turbo engines or GNC systems.
⚫ black (NBR):
Standard range of common use.
Suitable for low temperatures and basic applications.
�� Key fact:
The color of the O-Ring is not only decorative, but also identifies the type of material and its specific resistance for different working conditions on the engine.