Large, front-load main compartment. Slide-access hydration compartment with shoulder strap hose jacket, holds a 2-liter reservoir. SLIDELOCK reservoir has a wide opening to make it easier to fill, add ice and clean * Insulated water tube cover prevents water from freezing in the tube. Hinged front pocket holds a helmet. * Front zippered pocket holds bicycle tools, accessories or media player. Vapel mesh adjustable backpack straps * Tuck-away, adjustable waist belt secures the pack Reflective loop holds bike LED blinker. * Size: 17.0" x 11.0" x 5.25" Capacity: 600.0 cubic-Inch Weight: 1.51 lbs. Materials: Grid-Weave Duralite, Shiny Mini-Waffle Weave