I have these in my car for drilling out old subframe bushings and they work great! You turned a 3 hour job into a 30 minute job. I've used 2 different sizes and each blade stays as sharp as it came out of the box. They came in a beautifully organized case to keep everything together and organized. They are very easy to assemble and resize the blades. The instructions were easy to follow. The quality of the metal is excellent, I'm sure they will last a very long time. The price is much lower than most of its competitors, but the quality doesn't suffer.