Total of four compartments: Main compartment: 18″ x 10″ x 5″ with one zipper and one mesh pocket. 2nd compartment 15″ x 8″ x 2″ Front top compartment: 4″ x 7″ x 2.5″ Front bottom compartment: 10″ x 8″ x 2.5″ Hydration compatible 18″ x 10″ x 10″ 1362 in³
