[HeadlessNorseman]

I forget what they are called, failsafe maybe? but they go inline with the throttle servo that will apply neutral or full brakes whenever you go out of radio range. You should have one on every gas car you own, cause they can end up flying and really destroying other things. As far as ofna motors, they are very finicky. I have a thunder tiger 21 in mine and it makes more power than the stock one and runs great, all the time. I just need to tune it a tiny bit between winter and summer.