This specification has been declared NONCURRENT by the Aerospace Materials Division, SAE, as of April 2007. It is recommended, therefore, that this specification not be specified for new designs. NONCURRENT refers to those specifications which have previously been widely used and which may be required for production or processing of existing designs in the future. The Aerospace Materials Division, however, does not recommend these specifications for future use in new designs. Primarily for bearings requiring self-lubrication, low coefficient of friction, and accurate dimensions.