Just took this to Nepal. Worked great. This is more a note that I certainly didn't see the 125 litre battery life other folks here seem to have gotten (granted I purified a litre at a time, not 16oz). On rechargeable NiMh batteries claiming a 2000mah capacity, I got 31 litres out of the first set of batteries. With the second set I brought, I had unfortunately left them loose in a plastic bag. Unknown to me at the time, as the batteries bang together in the bag (even without completing a circuit), they will slowly discharge each other (I figured this out as I was moving stuff around in the tent and saw small sparks as the batteries contacted each other). A strip of masking tape to keep 'em in line would have saved me some grief. So, I bought a set of duracell titanium alkaline batteries. They finished out the trip at 13 litres with a little gas left, but they had to 'rest' between litres for a couple of hours (the NiMh batteries would do 3 litres back to back no problem). Maybe my NiMh batteries are the problem, maybe it was zapping multiple litres in succession, but I'm not picturing 125 litres out of any set of batteries (even if they're rated 2600mah). Don't take my word for it, though, try 'em out before you go -- give 'em a full charge, and zap a litre morning and night for two or three weeks (or however you expect to use them) to see how long they'll last you. Consider buying a bunch of Propel (or similar) flavoring packets for the water, too, it makes the off taste stuff a lot easier to drink for your wife :)