The HydraHike hydration backpack is comfortable, convenient and made to last for all adventures. Main compartment is accessible through top zipper. Lightweight ripstop fabric. Insulated reservoir pocket + 2L wide slide reservoir included. BPA free reservoir has bite valve with on/off switch. 360° reflectivity. Full-length main compartment. Front accessory pocket with organizer. Quick-stash gusseted pocket with compression straps that unbuckle to attach gear. Adjustable waist belt with pockets. Exterior daisy chain for attaching gear. 18″ x 12.2″ x 5.5″(Color :Grey Blue)