Form: This specification covers a high temperature fluid resistant perfluorocarbon rubber in the form of molded o-rings. Application: Sealing rinc~s for use in contact with air or a variety of fuels@ lubricants and hydraulic fluids from -15??to +290??(5??to 555??. Each application@ however@ has to be considered individually. Instances are known when this material has been used below -15??(5?? and also above 290??(555??. The cross section of such rings is usually not over 0.275 in. (7.0 mm) in diameter or thickness. Standard sizes are as shown in AS 568.