Main compartment with dual zippers: 17" H x 12 " W x 4" D. Second compartment with dual zippers: 17" H x 12 " W x 2 " D. Front dual zippers compartment: 12" H x 10" W x 1 " D.  - 3 pen holder, 1 accessory pocket.  2 mesh bottle water pockets. Bungee system on the front for attaching extra gear or accessories. S-shape padded adjustable shoulder straps. Padded back panel. Haul handle. Material: Polyester.  Does NOT include Pens, Pencils or Calculator.  Choose color: Gray or Red.  You will receive 12 of the color you choose.