The go to option for hydration while cycling, the CamelBak Classic 70 oz. Hydration Pack features external access to the reservoir for convenient filling and just enough space for carrying the essentials. . . . 2L Antidote reservoir has a quick snap cap for easy opening and closing, a low profile fit for more stability, and a lighter fill port to cut weight. Quick Link system allows the tube to be disconnected from the reservoir for easy filling . Extra large opening makes the reservoir easy to fill and clean. Convenient external fill reservoir. Single zippered pocket for holding keys, wallet, or other small essentials. Bungee on back panel allows you to lash a layer to the outside of the pack. Front and rear reflective details help keep you visible in low light .