Sets (two) bought for a seven-day trip in the mountains in the Balkans - for use with stagnant water, collected rainwater from containers, and other rare water points along the trail. Let me say right away - no one experienced any stomach issues. So, it probably works :) Handy, works in various configurations (filter inside the bottle, filter on the bottle, filter as a separate straw, bottle without a filter just as a bottle...), and reassembling the setup is easier than Lego bricks. Additionally, I think only this set on the market has the option to purchase a compatible carbon filter (chemical filtration). The water flow rate is slower than in a similar Sawyer set, but still satisfactory and NOTE! the water was slowed down for us by the carbon attachment, which my friend with the Sawyer did not have. Without the carbon addition, it works comparably to the competitive Sawyer product. Durability: The navy blue bottle purchased at the same time lasted without any problems, despite intensive use for a week in the mountains. However, the gray bottle slightly delaminated at the seam at the very bottom (I am currently preparing a complaint), but the defect was so minor that a small piece of repair tape fixed the issue.
