"Go ahead and pack a few extrasthe Gregory Arrio 28 won't weigh you down. This lightweight daypack is designed to move with your body while providing plenty of airflow and easy access to the essentials you need for longer day hikes. The flexible CloudControl hipbelt provides stable support as you move, while the VaporSpan tensioned backpanel uses engineered mesh for uninhibited airflow and mapped support. A breathable shoulder harness with perforated foam and open mesh keeps things comfortable, and the sternum stability strap includes an integrated safety whistle and hydration-hose routing clip. A quick-access zippered top pocket provides secure storage, while the 2-pocket design offers large main-volume storage and a front zippered panel for additional organization. Dual stretch-mesh side pockets large-format bottles. An internal hydration sleeve with a SpeedClip hydration hanger is compatible with Gregory Hydro reservoirs (not included). The trekking-pole system includes an elastic bungee loop and lower webbing attachment. Made of nylon ripstop and polyester. Manufacturer style #: 157885-A482 Lightweight daypack design for longer day hikes Flexible CloudControl hipbelt VaporSpan tensioned backpanel Breathable, foam-filled shoulder harness Sternum strap with safety whistle and hose clip Quick-access zippered top pocket and two-pocket organization Dual stretch-mesh side pockets for large-format bottles Hydration sleeve with SpeedClip hydration hanger Trekking-pole systemSpecs: Capacity: 1,709 cu. in./28L Weight: .94 lbs. Reservoir capacity: 2L/3L. Torso fit: 16""-21"". Waist fit: up to 48""."