Bests & Worsts Reviews from Amazon

In general, the water filter works wonderfully. Specifically there are a couple of limitations built in to the product. First, it isn’t really gravity fed, the filter is fed by pressure provided by squeezing the container holding the pre-filtered water. I’ll admit that the pressure doesn’t have to be much to provide a steady stream of water. I suspect that the problems people have with the bag is that they try to force the water through the filter too quickly and tear the bag. One of the built in problems is that the container which has the unfiltered water in it and on it is above the filter and the container that will hold the filtered water. One would want to wipe the unfiltered water container of most of the water on its exterior to keep the filtered water container as clean as possible. I bought the filter with a sixteen ounce bag for the dirty water. Using the filter convinces me that the 16 ounce bag is too small. The bag isn’t completely emptied when it is used so collecting a half gallon of water for example would require many repeated filling and draining of the water bag. There are two easy solutions: A. Buy a 32 ounce water bag B. Bring along a two liter plastic bottle. Emptying a two liter plastic bottle is much quicker than and equally as easy as emptying the bag. Neither the bags nor the plastic bottle have valves so eventually a partial vacuum forms in them although it is an easy matter to invert the filter and container and release the coupling to allow air into the container. When the filtering operation is finished one must remember to move the dirty water container away from the clean water container to avoid accidental contamination because the bag retains a little water. All in all this is an excellent water filter for the backpacker and I'm very happy with my purchase.