I used LifeStraw LSFX01GB01, I took this backpack on a trip to PA It's very light, easy to use and eco-friendly. I had a hard time getting it to work initially. You have to use pistons for things to work out. The water came out slowly and I filled a bag with 3 bottles of water and still had water left to use after dinner. I was shocked to see how well it filters! I scooped the water from the cistern and once it was filtered, it tasted so good!