This is an awsome water filter! You fill the bladder, hang it up, and let gravity do the rest. I have found that the flow is no quite as high as advertised, but it will filter 4 liters in under 4 minutes. I have had no trouble backflushing the filter element. I also like the fact you can fill the bladder and yo don't have to fliter the water right then... you can have water on demand! Everyone who has seen mine in action has wanted one for themselves. The bladder can hold up to 6 liters of water, but only has markings for 4 liters. It can take some creative thinking to fill the bladder under some circumstances, but I have always been able to fill it. I would recomend this filter to anyone.

I've backpacked in the California mountains for the past 9 years, and this is the best filter ever. I have carried pumps with paper cartdidges (never again) and I have carried MSR water pumps that have made excellant water and were easy to clean, but this new Autoflow was fantastic. We had a group of 7 and we were able to fill all our water bottles and get tents setup and meals prepared. There was a one-time learning curve about not putting the cap on the nalgene too tight (the air has to escape for the water to go in) and the same thing when backflushing the filter. Everyone wanted a turn using it and it is now back in the wilderness with a local Scout Troop, so I'll see how hardy it really is.
Thanks MSR.

I recently used this filter on a backpacking trip with a 6L MSR Dromedary Bag.

PROS: It performed well and I could fill my Dromedary bag all the way without having to pump. While I don't carry 6L around with me, it is nice to be able to filter enough water for 2-3 people without any work. The filtration rate was fast, about 1-1.5L/minute, but the water was of good quality. There is a sediment screen on the big bag to prevent junk from getting in the tube. It can also directly connect to wide mouth Nalgene bottles. Supposedly can filter 1,500 Liters before a filter change.

CONS: Backflushing didn't work well on mine. The filter worked fine in the field, but I tried to backflush at home to clean it out. Doesn't work in freezing temps, but most filters don't work in freezing temps. Regular maintenance is required.

Buddy brought this on a climbing trip this spring, best water filter I've ever used.

Just fill the bag up, connect the filter, and presto quick easy filtered water.
So quick and simple there's no need to hang it up, you can easy refill water bottles in a couple minutes, then it packs down super light.

Extra plus: use it to fill up your water bottles, refill the bag, and then carry unfiltered water in the bag until your bottles are empty, then use that water to refill again. Can't do that with a normal filter.

Amazing that the whole waterfilter industry hasn't gone to gravity systems. So nice to be able to deal with other things while the water filters... surprisingly fast, and the system is super lightweight and easy to clean. Brilliant.

I just came back from 7 days in the Pasayten Wilderness in north cascades, this filter was my favorite piece of gear. It worked flawlessly - and made something that is usually something of a cold chore into something that took no time and no effort - it just worked in the background and there was water when I needed it.