I wanted to cut out a dryer air vent, some cat door holes in the interior hollow doors and some holes for the radio antenna wire. I didn't want to spend $30-$40 on a hole saw (local big store) just because I'm going to use it a few times. This set did the job, but it's pretty flimsy. The square piece you see in the bottom right picture of the case is a retaining clip for large saws and is a slotted hole that fits into the bare shaft. The part is made of mild steel and bends easily. The small pins that go into the saw blade are curved. I straightened the studs and tightened everything really tight to hold everything together while I drilled and made holes. I don't know how many more times this can be used before something goes beyond usability. It's definitely NOT something even close to a good quality saw, but for the price it barely did the job. Although I made my holes I only give it two stars, it's cheap and fragile and I don't want people to buy it thinking they're getting value for money.