The MR509 Personal Locator Beacon is designed for use as as urvival radio by aircrews, mariners and personnel engaged in other military missions, operation of theMR509 is initiated manually or automatically ,when activated, the unit transmits an intermittents , weep tone radio distresssignal in theUHF/ VHF aviation frequency bands and messages on the COSPAS–SARSATsatellitefrequency, the MR509 can be tested simply and quickly before ever mission or at regular intervals by activating theBITE, a yellow light and an audiosignal gives an instant „GO/NO GO“indication, the unit is waterproof to a depthof 10 m, the battery has a lifeof 5 years, this device is used but in very good and beautiful condition, device has not been tested, the device is used by the manufacturer for training purposes, various frequencies are deactivated or changed for training, very, very rare and hard to get,Please note that all our items are pure collector items or display items. The items are not tested for real use and have no aeronautical exams or clearances. Use is at your own risk !