The Ultra Trail du Mont Blanc marathon consists of 103 miles with an elevation gain of 30,000 feet, and the CamelBak Ultra 10 Hydration Vest outlasts it all. Designed specifically to meet the UTMB's extensive gear list, the Ultra 10 has more than enough room for food, water bottles, ultralight rain gear, layers, pants, survival blankets, trekking poles, a headlamp, phone, compass, and hat. The cargo compartment expands so you can fit more items beyond the UTMB's list. CamelBak included a 2L Antidote reservoir with an easy to open Quick Link system, HydroGuard antimicrobial technology, Big Bite Valve, and PureFlow tube. The Ultra 10 Hydration Vest has external fill capability that allows you to refill while running. CamelBak made this vest with reverse chain nylon for durability, padded mesh for breathable comfort, and open mesh at the shoulders to ensure proper ventilated airflow throughout all your marathons.