Dimensions: 9.5" x 12.5" x 18". Weight: 2.5lb. 600 Denier PVC lined polyester construction. Four expanding compartments that provide up to 20 liters of storage. Internal dividers and zippered pockets are built in the three largest compartments. The mesh padded back panel can hold up to a 2.5 liter hydration bladder (bladder not included). The contoured shoulder straps are constructed with mesh padding and are fully adjustable. Adjustable waist strap and sternum strap. MOLLE system straps. Reinforced carry handle. Mesh ventilated padded back with Velcro top closure. Shoulder straps have hard plastic D-rings for attachments. Four quick release compression straps for expansion and consolidation. Medium 2 liter external organizer pocket.