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.
Hydrogenated Nitrile Specs:
- ASTM D 1418 Designations: HNBR
 - ASTM D 2000, SAE J200 Type/
 - General Temperature Range: -25 to +300 Degrees (F)
 
HNBR Performs Well In:
- Automotive applications
 - Oil field applications
 
HNBR Does Not Perform Well In:
- Esters
 - Ethers
 - Hydrocarbons (chlorinated)
 - Ketones