This past summer I made a gravity filter from some silnylon, a katadyn Pur hiker filter, and some tubing (using some instructions I found online that I can't seem to find now). After a few years of using aquamira I'm not sure if I will go back. That darn thing was awsome...I think my one complaint was having to hold the filter when there wasn't anything else willing (eg above treeline or with my wife)