Light and simple, the nke Crew Transmitter automatically triggers an audible Man Over Board alarm, whatever your instrument system, and displays bearing and distance to the Man Over Board to facilitate rescue. The transmitter continuously sends its ID code to the system and in case of radio signal break, you are immediately warned. It is strongly recommended for children and navigation by night. Each installation can handle up to 8 Transmitter units. Power supply: lithium battery 3.6V. Battery life time ranges from 1 to 3 years. (Return the unit to your dealer for battery replacement). Operating temperature: -10°C to +50°C. Storage temperature: -20°C to +60°C.