What size of the camelback hydration bladder...
What size of the camelback hydration bladder will fit to this pack?
I believe this fits anything up to a 3L bladder.
It will accomodate up to a 3l camelback, and any of Osprey's bladders. One thing though - there is a pocket, but you'll have to put in your own hook to keep the bladder from sinking to the bottom of a lightly loaded pack. It's easy to sew in a fabric loop to hang it from though - that's what we did. 5 min and $.25 worth of paracord. Alternately, you can skip the camelback, and get an Osprey hydration bladder which has a rigid back pannel and stays straight in the hydration sleeve.