Bicycles Derailleur Hanger Alignment Gauge,Bike Tail Hook Calibration Tools for Mountain Bicycle(red)

I whacked my derailleur pretty good and knocked the hanger visibly out of alignment. So I figured I'd try this tool out to fix it. I just unboxed it and put it to use, so I've used it exactly one time.Out of the box, the tool is very red and shiny and feels substantial. There's a small vinyl cap on the derailleur threads, which is a nice touch. The first thing you notice is that there's no friction on the sliding extension, so you have to use two hands to hold it in position.After screwing it in to the derailleur hanger, you notice that the tool has some play. This is not a precision instrument, but I don't think you can expect that for the price. If you're careful and take your time, it is possible to get some reasonable measurements with the feeler by holding the tool consistently to take up the slop.Fully extended, the tool does have enough leverage and is strong enough to bend the derailleur hanger in the direction you want to go. It took me about four bends to get the derailleur hanger back into a reasonably good position.Are the results perfect? No. But my shifting does work again. Was it easy to use? It was a little awkward, but possible to make it work.Best of all, it was cheap and did the job.