Used once, not including bladder for sanitary reasons. Fits a 2.5L bladder (photo shows the size, but not included.) Essential hydration and storage for longer hikes 13.5-liters of usable cargo storage on the trail 2.5-liter Crux reservoir allows for convenient hydration Air mesh suspension and s-shaped straps for comfy carrying Roomy interior for extra layers and larger items Front organizer separates your smaller accessories Side stretch pockets provide quick-access to snacks