O-Rings are round rubber washers that are placed around the valve stem in order to create a seal, preventing leaking from occurring and providing an excellent resistance to vibration. The listed size is referenced from AS568 dimensions, which is the Aerospace Size Standard for O-rings from the Society of Automotive Engineers.
Flurosilicone Specs:
- ASTM D 1418 Designations: FVMQ
 - ASTM D 2000, SAE J200 Type/
 - General Temperature Range: -70 to +350 Degrees (F)
 
FVMQ Performs Well In:
- Hot air
 - Hydrocarbons (aromatic, chlorinated, nitro)
 - Ozone
 - Sunlight
 
FVMQ Does Not Perform Well In:
- Hydrazine
 - Brake fluids
 - Ketones