Longer miles on the trail demands a pack that can accommodate enough gear to fuel, hydrate, and keep you safe over the long haul. Osprey's Duro 6 includes a run-specific 1.5L reservoir and two extra-large stretch mesh harness pockets into which you can slide 500mL soft flasks (not included). Slide your essentials and whichcever nutrition you choose into four additional lower stretch mesh harness pockets.You're not gonna wear it if its not comfortable, and if that's the difference between logging your run and surfing social media on your phone - well, your running vest better be comfortable! The Duro 6 features a 3D Spacermesh bodywrap for lightweight padding, full ventilation, and irritation-free contact surfaces. Add to that an adjustable chest strap for stability and multiple sizing and you've got a vest that will not only fit, but add comfort to demanding and technical trails runs.