Perfect for any run, the Nathan 18oz Insulated Soft Flask lets you carry your water and keep it cool. Nathan designed the soft flask to fit perfectly in front hydration vest pockets, or as an extra in the back storage or stash pocket. The soft sides make it easy to hold, and the 18oz capacity ensures you’ll have enough to get you out and back. A classic bite valve makes it easy to take a quick drink while you’re running, and it closes securely to keep your water from leaking out. With insulation to keep drinks cooler 38 percent longer, the Nathan 18oz Insulated Soft Flask is the ideal running partner.