Form: This specification covers butadiene acrylonitrile (NBR) rubber in the form of molded rings. Application: Primarily for use in aircraft fuel systems operating from -55 to +125 ??(-67 to +257 ??. These rings contain less plasticizer than normally used in aircraft fuel seals; therefore@ there is less shrinkage when the rings are dried out. Safety-Hazardous Materials: While the materials@ methods@ applications@ and processes described or referenced in this specification may involve the use of hazardous materials@ this specification does not address the hazards which may be involved in such use. It is the sole responsibility of the user to ensure familiarity with the safe and proper use of any hazardous materials and to take necessary precautionary measures to ensure the health and safety of all personnel involved.