Tiny UV Light ‘Wand’ Destroys Microbes in Bad Water


For the past couple years, while backpacking in the wilderness and on international trips, I have relied on a device called the SteriPEN to purify water. The battery-power “pen” emits UV light that destroys bacteria, viruses and protozoa such as giardia and cryptosporidium to provide “germ-free” water with the press of a button. Sounds like magic, I know. But the SteriPEN is actually just a scaled-down version of the same kind of UV-light purification system that many municipalities in the United States employ to treat mass quantities of H2O.

UV light is the purifying mechanism in SteriPEN products; AdventurerOpti model (left) and a lab test

To use a SteriPEN, you dip the unit’s glass lamp into a cup of clear (not silty or clouded) water or a bottle and stir gently for about a minute as the UV light flashes in your drink. Once finished, the lamp turns off. Presto, your water is good to go!

As noted, I use the product outdoors and traveling internationally. My review article last year details one of the company’s products, the AdventurerOpti, which I took around the world with me in 2010.

New this fall, SteriPEN’s magic purifying wand comes in a tinier and even more travel-friendly design. The company’s Freedom model, which costs $120, is the smallest and lightest SteriPEN yet, weighing just a couple ounces and fitting in any pocket at 5 inches long.

SteriPEN Freedom model

It is also the easiest model to use. You do not even need to push a button to operate it — small sensors near the lamp know when the unit is dipped in water, triggering the UV mechanism to turn on and begin to disinfect. Once complete, the lamp shuts down and the unit’s green L.E.D. blinks off, telling you the water is safe to drink.

Another upgrade: The Freedom pen has an integrated battery that recharges via a micro USB port. You can plug it into a laptop computer, an AC wall outlet (with an included adapter), or, for backpacking, a compatible solar charger. The company specs 40 purifications between each charge, enough UV juice for all but the longest wilderness trips.

—Stephen Regenold is editor of GearJunkie.com. Connect with Regenold at Facebook.com/TheGearJunkie or on Twitter via @TheGearJunkie.

Purify in a glass or a water bottle outdoors

Stephen Regenold

Stephen Regenold is Founder of GearJunkie, which he launched as a nationally-syndicated newspaper column in 2002. As a journalist and writer, Regenold has covered the outdoors industry for two decades, including as a correspondent for the New York Times. A father of five, Regenold and his wife live in Minneapolis.