I got mine in the post from Tarty today, ive been waiting ages for someone to bring out a simple tensioner like this. Im very impressed with it, its easy to install, lightweight, and you can see it adjusting the tension of the chain all the time, and therefore keeping it tensioned at all times. Whereas with my previous fixed tensioner, my chain was tight on one half of the turn, and loose on the other. The tension is quite tight and i cant see there being any way of the chain falling of the side.