If you ever hear someone mention "Phoenix, AZ," and "summer" in the same sentence, the word "hot" probably comes up at least once. If you're in Phoenix, there might even be some colorful adjectives surrounding the word.
You might also hear people mention that it's a "dry heat." Let me tell you that "dry" doesn't quite do it justice. It's regularly below 10 percent, and I've seen it as low as 2 percent.
At that point, no matter how much water you drink, you still feel parched. Dehydration is a serious, serious concern. People have died while hiking because they only took along one bottle of water.
Now, imagine the danger for construction workers, athletes or soldiers working hard in the same environment. That's why the Sandia National Laboratories, the University of North Carolina and North Carolina University came up with a solution.