WS-220WX WeatherStationA(R) - No HumidityAirmar has restructured the WeatherStation range. The updated models are designed specifically for marine use. The WS-120WX and WS-220WX do not include humidity as standard. Instead, an optional add-on humidity sensor is available to field-upgrade either of them, or as a kit when you purchase one of these sensors. Adding humidity sensing is a simple plug-and-play two-screw installation and can be completed at any time by any skill level. A heater option will also be available, resulting in a total of six assembly numbers available for the recreational industry. Features:Apparent wind speed & angleBarometric pressure a 'a 'a 'IPX6 waterproof rating a 'a 'a 'a 'Air temperature plus calculated wind chill a 'a 'a 'a 'Optional field-serviceable relative humidity with calculated dew point and calculated heat index a 'a 'a 'a 'Optional heater and upper ring a 'a 'a 'a 'NMEA 0183 & NMEA 2000 output a 'a 'a 'a 'True wind speed & direction a 'a 'a 'Internal GPS position, speed over ground, course over ground a 'a 'a 'a 'Three-axis solid state-compass with dynamic stabilization a 'a 'a 'Three-axis accelerometer for pitch and roll a 'a 'a 'a 'Three-axis rate gyros for rate of turn