When a simple daypack won't due, try The North Face Enduro Plus Hydration Pack. This hydration-specific day pack offers the support and size needed for extended endurance runs days on the trail. The pack's form-fitting waist belt and shoulder straps support the weight of the two-liter reservoir, while the advanced Enduro Boa® technology lets you dial in compression to further snug down the reservoir and reduce sloshing. Reflective trim adds low-light visibility, while the lightweight Siloxane ripstop nylon keeps the overall pack weight in check. There's a trekking pole attachment on the outside, 580 cu in of internal storage and an easy-access front pocket for small items.