Taking your training routine outside? The REI Stoke 19 will help keep you doing laps over rocks and pine needles. Backpanel is lined with highly breathable, moisture-wicking, ventilating mesh to move sweat off your back. Egg-crate-shape foam backpanel follows the contours or your body, keeping pack contents close in and stable. Pack features an internal cord compression system that pulls the load in with one tug, eliminating external straps and buckles. Adjustable, padded and wrapped with breathable mesh, the perforated foam shoulder straps enhance air circulation. Stabilizer wings connect the shoulder straps to the bottom of the pack to stabilize the load and reduce unwanted bouncing. Hipbelt webbing system cinches with a natural forward pulling motion for quick, precise adjustments. Panel-loading zippered main compartment carries the essentials you need for a workout on the trail. Deep front zippered pocket features a key clip and two mesh pockets for cell phone, wallet and small essentials. Separate zippered pocket holds a 2 liter hydration reservoir sold separately for hands-free drinking on the trail. Innovative feature directs hydration sip tube out through either shoulder strap. Twin hipbelt zip pockets store those small essentials you want at your finger tips, such as lip balm, sunscreen and digital camera. Two mesh side pockets provide storage for slightly larger items, such as energy bars, MP3 player and a small energy drink. Clip loop lets you attach a safety flasher.