HYDRAPAK reservoir bladder and drink system included Sleek Air Flow design profile pack with separate hydration pocket Internal posh top drop-in audio pocket with headphone exit port Multi-use large main compartment and posh valuables pocket Dual side mesh accessory pockets and expandable front mesh pocket Adjustable padded shoulder straps with sternum strap Deluxe back padding with air flow channels for ultimate cool comfort 70 oz/2.0L Bladder ? FDA Approved Polyurethane MATERIALS 600D Poly PU2 / 420D Dobby Poly PU2 / 400D Nylon PU2