NPTF Pipe Hex Reducer Bushing. 5406 NPTF Pipe hydraulic fittings correspond to the following: Aeroquip 2081, SAE 140140, Parker Hydraulics 0102, Weatherhead C3109. Material Composition: Fittings from forged or cast pressure resistant carbon steel with a zinc-trivalent anti-corrosion coating. NPT and NPSM are pipe thread. NPSM is straight while NPT is tapered. Female National Pipe Straight Mechanical (NPSM) fittings incorporate a 30° seat against the male creating a metal leak resistant connection.