works for me
I have used this filter for 2 years now with out any problems. I still have the original filter in it. (I keep an extra one on hand just in case). During the summer it gets used on a regular basis. It has never let me down and i have never gotten sick. I will take this on a 4 day kayak trip with out any worries. The key is to try and use flowing water. If you stick it in a mudd puddle ya it gets clogged easier.