The wireless masthead transmitter outputs NMEA 0183 wind speed and direction data via its paired receiver box. It is powered by an internal battery which is charged from ambient light using a small solar panel. A few dull days will not affect performance. When fully charged, it is capable of two thousand hours of full operation in total darkness. The masthead transmitter sends data wirelessly to the base unit, which is powered by the vessel’s 12 Volt supply, the base unit receives wind speed and direction data from the masthead transmitter and sends it to a Clipper Wind display or any other compatible NMEA display unit.