The High Sierra (R) Piranha 10L hydration pack is great for road biking, trail running or more leisurely hikes. Add-A-Bag attachment loops for securing the pack to a larger bag. 2-liter hydration system has a wide opening reservoir for easy filling and cleaning. System is BPA free. Insulated hose cover prevents water from freezing in the tube. Elastic loops for convenient hydration hose positioning. Large front-load main compartment holds gear. Organizer with key fob holds bicycle tools, accessories. Stretch front pocket for external storage. Airflow (TM) back panel helps channel moisture. Lightweight shoulder straps with adjustable sternum strap. Side compression straps stablilize loads. Tuck-away mesh sport flab holds a helmet.