What Our Gearhead(R) Experts Are Saying:"I've worn the Duro LT Hydration Pack on long training runs and fast-and-light trail days, and it disappears once you strap it on. The front flask pockets sit right where you want them, and the 3D Spacermesh back panel keeps airflow moving so you're not soaked through before mile five. It's the vest I reach for when I want to carry just enough without carrying anything extra."The Duro LT Hydration Pack was built for the kind of run where the plan is loose, the terrain is real, and stopping to dig through a bag is not an option. Osprey stripped this vest down to exactly what a trail runner needs, nothing more, and packaged it in a featherlight frame that moves with the body instead of fighting it. The 3D Spacermesh bodywrap keeps contact minimal and ventilation maximal, so heat moves out instead of building up. Both 360ml soft flasks are included out of the box, and the front pocketing system puts water, nutrition, a phone, and small valuables right where your hands land naturally mid-stride. A tuckaway safety whistle, removable dual chest straps for dialing in stability, and a large rear stretch mesh pocket round out a vest that covers every base without adding a single unnecessary ounce. The whole thing is built from 100% recycled materials and Bluesign-approved fabrics, so it performs well and sits lightly on your conscience, too.