Sterling Seal ORBN008x50 Number-008 Standard O-Ring, Buna Nitrile Rubber, 70 Durometer Hardness, 3/16" ID, 5/16" OD (Pack of 50) For use across a wide temperature range from -30 degrees F to 250 degrees F, Good/Excellent resistance to many petroleum oils/greases, hydraulic fluids, alcohol, mineral oil and grease Oil resistant applications of all types. Low temperature military uses. Off-road equipment. Automotive, marine, aircraft fuel systems Compatible with Aliphatic Hydrocarbons (propane, butane, petroleum oil, mineral oils and greases, diesel fuel and fuel oil) Not Compatible with product fuels with a high aromatic content; aromatic hydrocarbons (benzene); Chlorinated hydrocarbons (Trichloroethylene) Buna N or Nitrile has good mechanical properties when compared with other elastomers and high wear resistance. Good/Excellent resistance to many petroleum oils/greases, hydraulic fluids, alcohol, mineral oil and grease; 70 Durometer