You’re out camping. There’s snow everywhere. You’ve hiked for miles and are almost out of water. You’re parched and that’s going to make building a fire to boil more drinking water all the more difficult. Good thing you packed your SteriPEN Freedom.

The little $120 device harnesses the power of UV light to kill off 99.9 percent of bacteria you would typically find in a non-purified glass of H2O in less than a minute. You just shove the lamp in a 16 oz. glass of water (two treatments to sterilize a full liter) and stir it for roughly 50 seconds, with a green indicator light flaring up to let you know when the process is complete.

The Freedom is equipped with a rechargeable battery good for 40 treatments on a single charge. A USB cord and AC power adapter are included; the device will also play nice with compatible solar chargers.