It's nearly 100 degrees here at the Outdoor Retailer show in Salt Lake City, which is no doubt why everyone is buzzing about Columbia's new shirts and footwear with Omni-Freeze ZERO technology, which cool you down (a bit) when you get hot and sweaty. Four years in the making, the technology is actually fairly straightforward: The fabric is embedded with distinctive little blue rings that contain a special cooling polymer. When they're exposed to sweat or moisture, the rings swell a little bit. It's a mechanical reaction that requires a bit of energy to make happen, and all those swelling rings suck up just enough of the heat your body is generating to create a slight cooling sensation. Really? Really. We didn't believe it, either. But then we put the fabric and on felt it. The effect is less noticeable when you're hosing down the trail at full-tilt, but when it's this hot, every little bit helps.