I have used the Katadyn Pocket Filter for decades on bike tours through Alaska, Canada, the US, Mexico and S. America. It removes all bacteria and cysts and can be cleaned easily for a long filter life. A anti-viral supplement is advisable like Viral Stop. Mechanical filtering in my experience is more reliable for extended periods of travel. No battery or recharge problems as with UV products like the Steripen. No need to carry multiple replacement filters for some other pump filters that are not field cleanable.