They work well....

Do the first backflush before you leave home, if you can. Lots of info on Rokslide about hooking them inline with a platypus and using it as a gravity filter.

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Fine sediment will clog them, just like any other filter. Bring the syringe to backflush, at least until you know how how long you can run on a specific water source. Don't let it freeze or you will be buying a new one like me.