I need one Ive only really heard of them and I have a nitro trainer that my dad gave to me well more or less I inherited it when he died about ten years ago and yesterday I went to fly it like I reguarly do I had just taken off I wasnt even half way down the runway when the plane no longer responds to my control inputs I was only a few feet off the ground but I instantly think oh #$%$ what do I do if this thing flies off? well lucky me I only lost control for a second it came right back down I wasnt even at 70 percent throttle and it was kind of a steep climb I was going into so it stalled and smacked into the ground and it only broke the prop well I went straight up to hobby town and bought a new one and two frequency crytals one for the tx and rx and I also bought a new reciever and now my system works perfectly but I want a failsafe so if this happens again my plane will just cut off it would kill me to lose this plane by having it fly off into the horizon