Outdoor Products Gamma Internal Frame Technical Pack, 41.1-Liter Storage Lightweight aluminum frame system allows your back to breathe and provides heavy load support Suspended mesh back panel for maximum airflow Deluxe padded hipbelt, articulated, yoke-style shoulder straps with sliding sternum adjusters Large main compartment, front organizer, top stash- pouch and 2 zippered side pockets Hydration compatible, reservoir sold separately