Main compartment measures 18" x 9 1/2" x 5 1/2". approximate capacity 1400 cubic inches. Comfortable back padding and supple curvaceous straps supported by 1 1/4" nylon webbing minimize the load on shoulders. Two side net pouches with cinch cord can be used to carry water bottles. Lon thread (stronger than ordinary industry standard nylon thread). #AS-100 high grade closed-cell foam padding material for superior shock protection. High tensile strength nylon webbing. #10 high strength zippers and zipper tracks. Utx-duraflex nylon buckles for low sound closures.