This light weight, pack utilizes the AdaptiveFit system to conform to the runner! The VaporAir’s little brother has a game changing fit and contours to your form, regardless of change to your shape or size. ADAPTIVE FIT - Adjustable Sizing System provides a tailored, body mapped fit for all body types. Vest fit is snug and overall sizing tends to run slightly on the smaller side, so it is recommended that anyone on the higher end of a given size may want to size up! HYDRATION and STORAGE - Equipped with a 1.5L bladder for water and its quick release valve system, two storage pockets (one on each side, can fit bottles and flasks up to 22oz), large main storage compartment, one back kangaroo pocket for essentials and more. DESIGN – Designed for the man’s body shape. Lightweight and comfortable – no bounce, chafe-free breathable materials, and form fitting. Secure front shoulder zippered pockets. UNIQUE FEATURES – 360 degree reflective for runs in low visibility. Transparent zippered pocket for quick-viewing of essentials. IDEAL FOR OUTDOOR ENTHUSIASTS - Perfect for Marathons, Trail Running, Hiking, Walking, Cycling, Spartan Races, and Hydration-on-the-go! Specs FIT: Adaptive Storage Capacity: 244 cu in/4 Liters Weight With Bladder: 10.68 oz/302.9 g Weight w/o Bladder: 6.87 oz/194.9g