Nathan VaporAir Hydration Pack Running Vest w/ 2L Hydration Bladder Reservoir, Men's Over-the-shoulder load lifters keep water and gear close to the body for maximum no-bounce comfort SUPER BREATHABLE, body-mapped materials for maximum COMFORT Includes 2L bladder with quick-release valve POCKETS: Two front stretch mesh stash pocket w/ wipe clean surface for gels, front & side stretch mesh zip smart phone-compatible pocket, water resistant pill pocket Two EASY ACCESS front bottle pockets NO CHAFE, soft-touch elastic perimeter binding REFLECTIVE for safe night running Rear external shock cord for increased capacity WEIGHT: 14 oz /397 grams (weight includes bladder). STORAGE CAPACITY: 427 cu in/7 Liters without bladder; 305 cu in/5 Liters with bladder This product is intended to be close-fitting for the best performance. Please be aware that it may feel like a tight fit but that is the intended fit. If your measurements are close to the maximum size range, we recommend sizing up for comfort.