They are very practical. I have three sentences. I noticed that the large piece slipped as I drilled a lot of dowel holes, but I didn't tighten it as much as I should. The good thing is that they don't damage the wood surface any better than a block of wood, especially in hard-to-reach places. But hold her tight. If you're doing fabrication work and drilling lots and lots of holes, you may need a metal stop, but even then it should work fine. My only concern, hence four stars instead of five, was how far I could tighten the stopper without breaking it. Although it looks very strong. And the price is great. I bought more than one set because installing dowels requires readjusting the stop when going to a thinner piece of wood. With two, you can have a longer setting for edge dowels and a shorter second drill setting for square dowels. However, they are very easy to install and require no tools, so there is no need to search for a small screwdriver or Allen key. I recommend it.