To turn any pack into one that will hydrate you, opt for the CamelBak Stoaway Hydration Pack (100 Oz). This insulated, 100% BPA-free reservoir comes equipped with double the thermal insulation of a regular pack, and a 4 mm insulated PureFlow™ tube to keep water flowing. For an insulated reservoir that will transform your entire arsenal of packs into hydration-wielding mutants, reach for the CamelBak Stoaway Hydration Pack (100 Oz) and change your winter pack-life forever.