Reservoir: Quick Link System, 1/4 turn - easy open/close cap, lightweight fillport, dryer arms, center baffling and low-profile design, patented Big Bite Valve, HydroGuard technology, PureFlow tube, easy-to-clean wide-mouth opening BACK PANEL: Air Mesh HARNESS: Ultra-Light 3D Mesh Independent Suspension with gel pocket and Slider SternumStrap BELT: Fixed 1 in (25 mm) with cargo pockets Ultra-light materials, center expansion zip, essentials pocket, quick stash overflow storage, front and back reflectivity, safety whistle