The Nathan VaporAir Lite 4L Race Vest secures all your hydration and gear to your body while keeping weight down to a minimum to maximize comfort and convenience out on the trails.  With ample storage options, there is more than enough room for a day's supply of gels, capsules, gear, and extra hydration bottles (sold separately). Also, the included 2 L bladder supplies enough hydration to keep you going for hours on the trail. This vest's unique "Set it and Perfect it" fit system offers an adaptable fit that can be finely tuned to meet your body's specific needs, while breathable mesh materials ensure that things stay cool and dry regardless of the type of run or weather conditions.