What Our Gearhead(R) Experts Are Saying:"When I'm heading out for a long day on the trail-or even a multi-day fastpack-the Adventure Vest 17L is the only vest I trust. The fit is secure without being restrictive, and the amount of organized storage is wild. I can stash bottles, a reservoir, layers, food, and still have room to spare. The new wraparound fit feels locked in but comfortable, even when fully loaded."For unsupported long runs, backcountry loops, or fastest-known-time pursuits, the Ultimate Direction Adventure Vest 17L Hydration Vest is the piece we grab when we need to carry everything-without sacrificing speed or stability. Designed with input from elite ultrarunners and endurance athletes, this vest offers the most storage of any Ultimate Direction running vest, with an updated, body-wrapping fit that moves with you and stays bounce-free no matter how much you're hauling. The 17L volume includes thoughtful pocket placement from front to back: dual Hydrapak 500mL bottles ride up front (included), while large stretch and zippered compartments throughout the vest hold snacks, layers, trekking poles, and even bulky gear. The back panel includes a reservoir-compatible sleeve, water-resistant zip pockets, and quick-access stash options for puffy layers or rain shells. A new monomesh liner keeps airflow high and weight low, so you're ready to tackle big objectives with confidence.