What is the Hydro Rak?
Up until now almost all hydration reservoirs were designed to slide into a sleeve in the back of the pack. Once you put the reservoir into the sleeve it slumps to the bottom. Take a few drinks and it slumps more. Unfortunately water flow is directly related to the height of the water in the reservoir compared to your mouth height. All JanSport/Nalgene reservoirs have the Hydro Rak at the top of the reservoir. A toggle found at the top of the sleeve that holds the reservoir slides into the center hole of the Hydro Rak, keeping it high and tight, and insuring maximum water flow. To remove the reservoir, simply push the toggle out of the hole. Starting with packs made after January 1, 2004, all JanSport Technical packs that come with a reservoir or are hydration ready have the toggle at the top of the sleeve (you can tell by the red webbing on the toggle).
