Hydration packs are built as a backpacks or a waist pack and contains within it a reservoir in the form of a plastic pouch that holds liquid. Hydration packs have a connected hose to make drinking water, hands-free. Hydration packs are important for outdoor activities such as hiking, bicycling and kayaking as well as military operations. Hydration packs come with bladder and drinking tube and bite valve. There are also hydration packs that are essentially hydrapak reservoirs. Hydration packs store water and keep you hydrated for the long haul. Given the mechanism, hydration packs ensure that you get the right amount of water you need, thereby optimizing water usage when you don