gWind Transducer Only: The gWind transducer features twin-fin technology with 3-bladed propeller for more accurate TWS in lighter air while the twin-fin design gives a more stable TWA. The 3-bladed propeller, unlike a cups design, is always efficient. Combined with optic reading this transducer provides superior accuracy at low wind speeds and also provides for excellent linearity. This configuration includes only the gWind series transducer, making it easier for you to replace your device if needed. Included:gWind Transducer, Propeller installation instructions.