I used this on a few bikepacking adventures. Tour Divide, Arizona Trail 300, and a bunch of regional solo stuff. When it was working, it seemed to work just fine. I mean...I didn't get sick. During Tour Divide it got wet when in my bag. When I pulled it out to use it, it wasn't working at all. It had water inside it. I sat it in the sun every chance I got, charged it up every chance I got (using a cache battery and plugging into the wall), but it never came back. I will be sending it back for a refund. A water filter that can't get wet isn't any good to me. You should be able to drop the thing in the bottom of a lake and it still work....of course it shouldn't be able to disinfect the entire lake....but you smart ones should know what I'm talking about.
"Clear and easy to use. In my opinion, an improvement over other SteriPen models"
I really like SteriPen and think its an amazing alternative to other sterilization methods. I first saw one of my friends using the SteriPen Opti last year and thought it was a great product. However, that particular model I found difficult to read during daylight ours (theres a single small indicator LED) and it swayed me away from buying one. However, the SteriPen Ultra provides a BIG, BRIGHT, and EASY TO READ screen that makes the process very clear. It also offers a big count down timer so you know exactly how long to leave the thing in for and an icon to tell you how much charge is left in the rechargeable battery.My only worry with the product is that it can only be recharged with a miniUSB cable. This is fine if you are car camping or have a fancy solar panel set-up, but I would prefer to be able to carry back-up batteries just in case. Not a big deal if you are sure there is some charge left in the device.