Sizes: One size (fits chest range 82–116cm / 32–46in) Eidson’s original design was intended for mountain bikers, but CamelBak (and everyone else) now produce hydration packs for trail runners, hikers, ...

CamelBak founder Michael Eidson invented the concept of rear-mounted hydration packs (small backpacks containing a water reservoir or bladder, with an over-the-shoulder drinking hose, which prioritize ...