I had one in one of my planes for over to seasons and it would beep if their was no throttle action within a minute.I lost the plane in dense woods and when i went looking for it i heard the beep very faintly but could not locate it.After about three weeks of off and on searching i finally found it.What i trying to say is all it did was give me a general idea where it was located.When i did find it it had a dead batt and no beep.I think i could have found it without it just using line of sight when your plane gets in trouble.