NPUSA Men's Large Expandable Tactical Molle Hydration-Ready Backpack Daypack Bag Material: 600D High density polyester for daily rugged use. Removable USA Flag velcro patch Molle strap system: allows for attachment of external gear; D rings on shoulder straps; Side load compression straps to keep load tight Hydration Ready: water bladder pocket inside main compartment with hose/tube pass through hole at the top Excellent storage: 4 zippered side gusset pockets, 2 front zippered pockets, organizer, 1 main compartment Dimensions: 18.5"L x 12"W x 8.5"D; Volume: 2000 cu. in.; Expandable main compartment up to 2" extra storage space via perimeter zipper