Works, but dirty bag closure is moronic
"Great filter, though I use it in backcountry that has relatively clear water (doesn't clog the filter). Main gripe is the closure system for "Dirty" bag. It's printed on the bag "Zip shut to secure. Invert to test. " This is the worst advice ever. I posit it is nearly impossible to zip this bag, invert it and have the water remain within. I use this bag canoeing, I paddle out to the middle of the lake for water and I have to strap the bag to my leg after filling and have the bag hang from my leg until I return to shore and then have to struggle to get out of the tippy solo canoe while keeping the bag from spilling. I don't understand why one would pretend that it is possible to zip this bag closed and have it hold the water within. I dare the engineer that developed this system and printed the instruction on said bag to fill it with water, zip it closed and invert it over his laptop."