Innovative harness layout with soft, flexible edge binding provides comfort on the move On-the-go Z-Pole storage High stretch side panels add comfort and keep vest bounce to a minimum Front zip pocket with a key clip and removable micro race whistle Back zip security pocket and lumbar pocket Sizes: S, M, L Innovative harness layout with soft, flexible edge binding provides comfort on the move | Black Diamond Equipment Distance 4 Hydration Vest Backpack, Large Ultra Blue