SteriPen Adventurer Opti UV Personal Water Purifier for Camping Backpacking Emergency Preparedness and Travel Black Green Small

For anybody that wants precise numbers, mine weighed in at 127g with battery and case. The case is surprisingly heavy, you can save 28g if you ditch it and store this in a baggie. This product has some advantages over filters: it can't freeze, so no worries about having to keep it in your sleeping bag at night. And it's extremely compact and works with most containers you might run into traveling. Your water source has to be fairly clear and not brackish both for it to work and for the water to taste good so it's best to collect from a moving source such as a stream rather than a pond. Honestly my one complaint is the battery. It uses 2x CR123A batteries which weigh 32g together - a third of the pen's weight! Literally nothing else in a typical backpacker's equipment list uses that battery type, so a third of its weight is useless 99.9% of the day. I would love to see a version that took AAA batteries to save that weight. Read more

This was the absolute BEST thing we purchased for our recent Everest Base Camp trek. It worked like a charm, and we used it multiple times per day. We never had to purchase bottled/boiled water. Another great thing (depending on where you are at) is that the SteriPEN doesn't change the taste of the water. That was great up in the Himalaya (Kathmandu was a different story). I really wanted to get the USB rechargeable SteriPEN. Although it would have been perfect for camping, it was going to be a pain on our trek. That's why we purchased this version. We went through 2 sets of batteries and we were on our 3rd. It functioned perfectly; we never had an issue. This also works VERY fast as opposed to iodine/chlorine tablets. Those can take up to 4 hours to kill cryptosporidia/giardia. The SteriPEN "kills" everything in 90 seconds. Granted, that's "per liter", but it's still a lot quicker. The only downside I can think of is "one liter at a time". It worked great for 2 people. I would certainly look for some kind of gravity device for large groups (not to mention you "only" get ~50 liters on new batteries). EDIT: 3/29/2016 I've had this pen for almost a year now (can't believe it's been that long since I was in Nepal). It's still holding up to a 5 star review. We've since taken on a couple of trips (one time to Mexico and one time to Guatemala). After reading some of the other reviews, I feel like I should mention that this works best with 1 liter, wide-mouth bottles. I actually purchased a Camelbak Chute ( CamelBak Chute Water Bottle, Bluegrass, 1-Liter ) to go along with this particular SteriPEN (and I needed a new water bottle anyway). You can treat less than 1 liter, but you should never treat more than 1 liter at a time (and no ice). For example, you could treat a glass of tap water (as long as it's deep enough to make contact with the contacts). The SteriPEN never reached the bottom of the Chute. However, there was enough room to agitate the contaminated water by sticking the pen down in and then swirling it around. All I can say is that neither my wife nor I ever got sick using this system. Read more

The little gadget is a great addition to any hiking or outdoor trip, or trip to somewhere that your uncertain of water quality. We recently went to Bocas del Toro, Panama for 2 weeks. Most places in the area purify rain catchment water and it's drinkable. However, the last place we stayed at the shower water in our bungalow didn't have drinkable water so we used the Steripen when we filled our Nalgene water bottle and it worked great. I perform microbiological testing at a company and took the Steripen to work before my trip to do a little test. I performed Total plate count testing on a tap water sample and on the same tap water sample that I used the Steripen on. the tap sample had low TPC counts to start with (12 cfu/g), but the sample that I used the Steripen on had 0. It was a basic test and only one rep, but it was a little bit of my own data that made me feel a little more confident about using this item. It's compact and has a nice little case to travel with and super easy to use. Read more

Pros - small and good for travel, easy to use, battery powered so bring extra batteries. Cons - you need a wide mouth container and even with that, it will shut off if it slightly comes out of the water while you are rotating it - so then you have to start over. The drops around the rim aren't getting purified, so I would purify for 90 seconds, then put the lid on and shake then purify for 90 more seconds. That's at least 3 minutes per liter... and when you need 6 liters... that's kinda time consuming! The company recommends just wiping the rim and sides with a cloth... but nothing we had was clean enough for that. It works best for one person and with water that might be questionable and you just want piece of mind. I ended up losing it on the trip... and I won't replace it. Read more