Stratus II Tx transmitter is equipped with a GPS system for an accurate geolocation. It weight only 10 grams and can lasts 4 days with actualized GPS fixes every 30 seconds.
It send GPS fixes automatically thanks to a VHF link (Very High Frequencies). Battery level is indicated on the receiver and its batteries are simply rechargeable.
Stratus II Tx transmitters are compatible with any Stratus II Rx receivers.