We tiled the bathroom and used marble tile. We already had a wet tile saw for making straight cuts but needed to cut a few round spots for the plumbing so we decided to give this a try. They're a lot cheaper than most other bits like these, but they won't last long as they've just been treated with diamond grit. We only had to drill a few holes, so for us the cost savings was good compared to the level of usage required. If you do this frequently or for commercial purposes I wouldn't recommend them but if like us you do DIY renovations these will probably serve you very well for cutting tile or even countertops in marble, stone, granite, glass etc. Be careful Just be sure to use water when cutting.