The MSR Dromlite 2 liter and 4 liter Hydration Bags
I have recently made a move to lightweight gear, and smaller volume packs. I start early and hike hard so as to enjoy the afternoons exploring. I usually take a hammock withh a mosquito net and tarp, and enjoy hot meals at night. The Mountain Safety Research DromLite Hydration Bags (hereafter called the DromLite or bag) are collapsible, roll-able fabric water reservoirs. They are made of "MSR red" 200-denier Cordura which is welded together to seal the edges creating the envelope-type storage containers seen here. The fabric has a thick plastic-feeling coating on the inside. The MSR logo is applied to the face of the DromLites.
At the top of the bag is metal grommet that can be used to hang the bag on a nail or hook. A small carabiner, piece of cord or webbing can be placed through the grommet too. I have a hang strap from MSR on my 4 L bag.