The Vapor Air 7L 2. 0 Hydration Vest is Nathan's first face vest that features its innovative Adaptive-Fit Adjustable Sizing System to provide you with a precise fit for your runs and races. This system creates a fit and feel that feels almost tailored. It has two adjustment points that allow you to alter the waist and chest fit separately to create a body-mapped fit for your specific body type. Once adjusted, the vest stays snugly in place throughout your runs while the breathable, chafe-free construction ensures comfort through the miles. For convenience during your run, Nathan included a 2-liter bladder with a quick release valve for easy drinking. The Vapor Air also features multiple pockets to organize your gels, snacks, layers, soft flasks and bottles up to 22oz, and other essential gear. Additionally, bungee drawcord loops on the back accommodate your trekking poles when you don't need them. Finally, with reflective hits all around the vest, you'll be able to run confidently in low-light conditions when your runs last past sun down.