Whether you run, bike, hike or do some other form of outdoor activity, a hydration pack is an essential ingredient for making your activity a bit more enjoyable. The reasons are obvious: it keeps you hydrated without being a nuisance. Hydration packs can vary in style, so it is important to find one that fits your needs.
If you are looking for ultimate convenience and storage, then a hydration pack is your best choice. Hydration packs offer varying amounts of storage for different levels of liquid, so if you are going mountain biking versus a recreational bike ride, you may want a larger pack with a larger capacity of liquid storage.
You may notice that there are certain items called "reservoirs," and they are just as their name imposes. These reservoirs store liquid but do not have appropriate back straps, as they are intended to be used with compatible backpacks or daypacks. Most newer daypacks and backpacks have a sleeve to store hydration reservoirs, allowing you to enhance your current backpack with hydration pack capabilities. Check your backpack to see if it has an appropriate interior sleeve or compartment that can hold a reservoir, as well as a portal for the slip tube.
If you want a pack that will rest on your waist and come in the form of water bottles, then you should be interested in waist packs. Waist packs usually offer multiple water bottles, allowing you to store different forms of liquid for your needs. Also, some waist packs have a pouch where you can store supplies such as energy gels and an extra pair of socks.