The Ultra 10 was designed to endure one of the toughest trail races on earth: the Ultra Trail du Mont Blanc. This year, the most rugged vest gets an upgrade with even lighter materials and a 2-liter reservoir that delivers more water with every sip. This pack is designed for self-supported runs that take competitors through mountainous terrain and unpredictable weather. It’s engineered to hold everything on the UTMB packing list, including food, shed layers, a headlamp, trekking poles, maps and more. The custom-fit harness and dual sternum straps adjust for a stable, comfortable fit, and the cargo compression lets you cinch everything down to minimize bulk.