I first learned about the Life Saver water bottle from a TED Lecture. When you have the time, check the video out for yourself.
Lifesaver bottles filter down to 15 nanometers, which filters out bacteria and virus’. I relied on mine during a week long backpacking trip in Utah. I was expecting the bottle to be both a water filter and water bottle, but I learned that it should be used as a filter only. Be prepared with a separate vessel to store the clean water. I made the mistake of filling it and just carrying it around with me and having water leak on me and my pack.
Here it is strapped to the outside of my pack. It also fits nicely in the side stretchy mesh pockets as well as the front pocket