KEEP GOING This lightweight, hydration pack made of stretchy, open-air mesh will help you go the distance with its 7-liter reservoir, lined nutrition pockets, and flask pockets.   STABLE FIT The ergonomic strap system with adjustable bungee sternum straps and low-profile side compression system provide a secure, custom fit.   TRAIL ESSENTIALS Large and small pockets with and without zippers, a trekking pole carry loop, rescue whistle, and key clip help you stay safe and prepared on the trail.   Includes two HydraPak® 500ml SOFTFLASK™ Highly breathable open air mesh construction Three customizable and adjustable bungee sternum straps Fully lined water-resistant zippered stretch chest pocket Easy-clean silicone lined gel pocket Multiple front stretch mesh pockets with flask keepers Low profile fully adjustable side compression system Zippered reservoir compatible compartment Large back stretch mesh pockets Back security zippered pocket Low profile trekking pole carry Rescue whistle Reflective safety accents Key Clip 286g (Size M/L) Uses: Trail Running, Trail-Running / Training   Shell: 100% Polyester Shell Overlay: Power Mesh 86% Nylon, 14% Elastane