Inertia describes a tendency of an object to do nothing, so you might be confused why the Gregory Inertia 15L 3D-Hydro Reservoir Backpack is the perfect thing for your always-active lifestyle. Well that confusion should clear right up once you put it on. It's designed with a supportive and comfortable suspension system that features breathable foam shoulder and hip straps, a breathable back panel, and load lifters at the yoke that adjust the pack closer to the body for a more supportive carry. Included in the pack is a 3L hydration reservoir that sits securely in its own pocket, and features an easy SpeedClip mounting system that makes it easy to install and remove the bladder. When you need to reach for a windbreaker or rain shell you've got a buckled stretch mesh pocket that stores layers easily, as well as two stretch mesh side pockets in case you'd rather forgo the hydration system in favor of some good old fashioned water bottles. And the storage doesn't stop there thanks to the stowable trekking pole carrying system that'll help you fkeep your hands free on rocky summit slopes. There's also a convenient sunglass storage system on the shoulder straps, keeping your shades safe in a scratch-free environment without you having to take off your pack to stow them.