Baja Hydration Pack. Hit the road or trail with this sleek, versatile pack that keeps gear organized and you fully hydrated. 600 denier poly PU2/420 denier dobby poly PU2/400 denier nylon PU2 70 oz/2.0L HYDRAPAK reservoir bladder and drink system. Air Flow design profile pack with separate hydration pocket. Internal top drop-in audio pocket with headphone exit port. Large multi-use main compartment with valuables pocket.