Mil-Spec
Freudenberg N888: Low-Temp Aerospace Nitrile O-Ring (70 Duro NBR)
Freudenberg N888 is a 70 durometer low-temperature nitrile (NBR/Buna-N) O-Ring for aerospace: flexible to -65°F, qualified to MIL-G-5514 and SAE AS5440, built to AS28775, MS28775, and MS28784.
Military & Aerospace O-Ring Specifications: The Complete Reference
Every military and aerospace O-Ring spec in one place: M83248, M25988, M83461, MS28775, MS29513, NAS1611, AMS7276 and more, with supersession history and stock status.