There is a strong argument for hydration packs as the best outdoor innovation of the last few decades. Where once you had to stop, rummage around in your backpack for a water bottle, uncap it and take a drink every time you felt thirsty, all a hiker with a hydration bladder in their pack has to do is flip the cover off the bite valve and take a sip. There is no need to stop. The benefits for hikers, cyclists, horse riders, climbers and runners are easy to imagine. Many people find that they get through a lot more water with a system like this, and as a consequence, they stay more hydrated and feel less tired at the end of the day.
Mountain Safety Research Mini Works / Waterworks Maintenance Kit 56002
Mountain Safety Research Hydration Kit 57060
Mountain Safety Research 6 Liter Dromedary Bag W/ Fill Handle 57058