Form fitting running pack with versatile carrying capacity and stretch comfort for all-day endurance running. ADJUSTABLE SENSISHOULDERS: One size fits all adjustment of the shoulders for perfect fit. Can be easily adjusted from S to L, using the velcro system. EXPAND'DOWN COMPARTMENT: Expandable bottom compartment enables you to adjust volume depending on your load. One main compartment. Two chest pockets. Two lateral side storages. 1 safety pocket. 1 zipped black pocket. 4D pole holder. Under arm routing. 4D bladder insulated sleeve. Bite valve with on/off system. Plug-n-Play system. Soft 1.5L bladder - PVC, Phthalate, Bisphenol-a free.