After trying the Steripen Adventurer out on a 4-day trip last week, I'm returning it to REI.

I kept having the red light come on at the end of the treatment, requiring me to do each quart of water 2 or 3 times.

The amount of pressure required to turn the switch on really hurts whichever fingers I use, and half the time I can't get it to turn on at all. It's good that the switch is stiff enough that it can't be activated by accident in my pack, but not when I can't turn it on when it's time to use it.

I'd much rather sit in camp and watch the scenery while a gallon of water runs through my ULA Amigo Pro filter than to have to sit by a mosquito-ridden creeklet stirring the Steripen for what seems forever for each quart of water.

I tried using a cut-down 2 liter soda bottle, but it wouldn't fit the side pockets of my pack. So I had to take a Nalgene to have a wide-mouth bottle to use with the Steripen. The Steripen plus Nalgene plus extra batteries weigh at least as much as the ULA Amigo Pro. One thing that really bothered me was that after I dipped the Nalgene in the streamlet to fill it before using the Steripen, there was all this unpurified water left on the outside and in the threads. I ended up using Katadyn Micropur in addition to the Steripen for my grandkids' water because of this concern. By the second day I put the Steripen away for good and was using just the Micropur.

This is a very subjective report! Your Mileage May and probably will Vary! But this gadget is definitely not for me!