SteriPen Adventurer Opti UV Purifier

Instead of pumping water through iodine filters, this little pen uses an optical sensor and UV light to zap microbes like Giardia right in your Nalgene. Your water actually tastes like clean stream water, not pool chemicals. Rinsing a wand for ninety seconds feels like magic. The catch? You need CR123 batteries on hand, but for minimalist backpackers, it is brilliantly simple.