Here is another fitness tool that helps you stay hydrated as you exercise outdoors. Instead of carrying water bottles, you can wear the Wetsleeve on your forearm. It has 12oz capacity, a soft silicone mouthpiece, insulated layer to keep your water cool, and breathable fabrics to keep you comfortable.
Wetsleeve also comes with built-in pockets for your keys and other items. Expected to ship in October. More info is available here.