I bought these hole saws to use in my shower that I am renovating and they have worked great. The same size hole saw from Lowes was a lot more expensive so thought they might be worth a try and I'm glad I went with them. I had to cut two holes in a large veined natural stone tile, which made me very nervous. I used these bits in combination with a Revain bit that sticks to the tile which was very helpful. I can't tell what it will be like to cut a lot of holes, but for those who only want to cut a few holes, I highly recommend it!