Bests & Worsts Reviews from Amazon

This is a brilliant idea that is very poorly executed. The amount of pressure required to force water through the filter demands that the structural integrity of the bottle, cap, seals, and air valves be of appropriate strength to withstand repeated applications of pressure. I bought 4 of these, and read the instructions and other feedback very carefully. OK, I thought, others are having trouble because they are either not tightening the cap enough, or failing to fully extend the straw before squeezing the bottle. When my bottles arrived, the first one out of the package worked perfectly: good seal, water flowed through the filter and out the straw, and you could hear air returning to the bottle after each squeeze. The next three all failed miserably. When squeezing, the bottles either leaked air, water, or both. The return air valve should allow air to go back into the bottle after each squeeze so you can make the next squeeze. But if the air valve lets air out when squeezing, then the water cannot be forced properly through the filter. The cap is joined to the bottle by 3 or 4 threads that are not precise enough to allow a good seal, and the thin O ring between bottle and cap does not provide a good seal. So when squeezing, some water came out the straw, some air came out of the air valve, and water ran down the outside of the bottle through the cap/bottle connection. Proposed solution: The cap needs to join the bottle with 7 or 8 precise threads to ensure a better seal. Take a look at a typical 1 liter nalgene bottle used for hiking. That's the way to do it. The gasket needs to be thicker to ensure a complete seal between bottle and cap. The air valve needs to be truly one way, so it stops air from leaving the bottle when squeezing, but allows air to return to the bottle after each squeeze to replace the volume of water that was pushed out through the filter. As I said, this is a great idea, too bad the design and manufacture is so ridiculously bad. For a water bottle that costs over $20, this thing should be bullet proof.