Bought these to drill ceramic tile in my new shower to install a door. It worked. That's all I can say about it. It was less money than other brands and I drilled the 6 holes I needed in my tile but it took forever and I was exhausted by the end. The first was difficult, and as time went by they got more and more difficult. I was working on a vertical door so I couldn't fill it, but I kept a bottle of cold water nearby and often (partially) squirted it nasty. Why so long). After the fifth hole my husband came over to see why it was taking so long and asked if he could try and help me on the last hole (thinking I was doing something wrong or was just too weak). Soon he was sweating and realized it wasn't my fault at all, and this time I kept holding a stream of cool water while he drilled, so I wasn't bad at that either. Work and for me it was disposable as I probably won't need to drill through the tiles so I'm fine with that even though I lost some weight from profuse sweating wrestling. . :)