Providing enough space for water supply, clothing, snacks & all the essentials, the Camelbak Arete 18 hydration running backpack is an ideal companion for a quick hike. This versatile & durable backpack features a lightweight design, easily reverses into an insulated reservoir sleeve when not in use & offers a hydration capacity of 1.5L (50oz). There are adjustable backpack straps & a sternum strap for comfortable transportation & the Antidote® reservoir with a low profile design & a lightweight fillport uses anti-microbial Hydro Guard technology for protection against bacteria & fungus.