MIL-PRF-83870 Filter Element, Disposable, 20 Micron Absolute, Constant Speed Drive, AircraftThis specification covers constant speed drive \(CSD\) disposable filter elements that retain all particles larger than 20 microns. The elements are intended for use with lubricating oil conforming to MIL-PRF-7808 or MIL-PRF-23699 in the CSIs specified in 6.1.