The protector is included, but can be removed for hiking. There should be room for a 3l hydration bladder in the extra inner pocket.

Hey DarthShadow The hydration bladder is in another compartment (separated by a thin "wall") but the drinking volume is directly at the expense of the total volume. I can understand your uncertainty - I'm very happy with the 16l myself and wouldn't want a bigger one (as it's bulky), but on bigger tours it might be a bit tight.