Sterling Seal ORBN109x1000 Number-109 Standard O-Ring, Buna Nitrile Rubber, 70 Durometer Hardness, 5/16" ID, 1/2" OD (Pack of 1000) 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) Due to its excellent resistance to petroleum products, and its ability to be compounded for service over a temperature range of -65 to + 275 degrees F (- 54 to +135 degrees C)