Prevent Montezuma from getting his revenge

Neat. For your next trip to where sanitation is poor.

I took a SteriPEN to Africa for 3 months this summer and the verdict is in: it's the best water purifier you can carry without a tractor-trailer. It's basically a UV ray flashlight you submerge into your glass. The water stays cool and it doesn't change the water, except to kill all the living things in it, viruses included. It is expensive, but pays for itself quickly, as you don't have to buy bottled water. On my trip, often when I asked a waiter for a glass of tap water, my request would elicit a smile or a laugh. In some cases, they simply would not bring me a glass of water. Most of the time, though, I convinced them -- and then, to their amazement, I would take out the SteriPEN, push a button, and stir the water with the glowing purple UV light that always brought stares from other diners. After less than 60 seconds, I would take out the SteriPEN and drink the water, occasionally hearing gasps from other tables. Then I'd mention that UV light is how certain towns and companies now sterilize water.

In the 3 months I used it while abroad, I never got sick and the recommended CR123 batteries lasted all summer.