I personally purchased these for use with my pool as it is almost time to put it back up. I couple of years ago I had a lot of issues with keeping my pool water in the correct pH range, so this year I got this product so that I can quickly and easily test it. While these don't cover everything I need to know about my pool water, they take just a few seconds to work, so I can do a quick check with these and then go back to it with other products if there seems to be an issue. The really nice thing is that these can be used with any liquid, so can be used to test drinking water, bodily fluid acidity, or any other liquid that you may feel concern about. Since the litmus paper is not in actual strips, but is a roll, you can choose what size you need in order to do your testing, allowing it to last for an extra long time if you are conservative with your usage.