If you've ever been in an exotic locale, opened a "bottled water" and discovered a scent that reminds you of chili—and I'm not talking about the country—then you'll understand the importance of a good water purifier. The SteriPen has no dissolving tablets or plug-ins, you just stick it in a glass or bottle, turn it on and in roughly 48 seconds 16oz. of water is rendered safe and potable. It's particularly good at killing Cryptosporidium, a common cause of diarrhea and ruined trips to Mexico.
List price: $129.95
— Josh Tyrangiel