High Sierra Sentinel 65L Top Loader Hiking Backpack Pack features a rugged and comfortable design with dual contoured aluminum frame bars, a molded foam back panel with AirFlow™ channels for ventilation, and an ergonomic harness with a women's specific fit. This hydration compatible backpack has a large top loading main compartment and includes a front loading sleeping bag compartment, daisy chains for adding attachments, dual side mesh water bottle pockets, a front flap for added storage, and an internal hydration reservoir sleeve with dual tube exit ports.