Designed specifically for ultra-running, the lightweight, streamlined Salomon Sense Pro 5 Set vest pack has a dynamic, torso-hugging fit and keeps hydration and other race day essentials in easy reach. Two 500ml soft flasks are included. Salomon's motion-mirroring SensiFit design is the key to the pack's excellent fit and 'race' performance. Completely supported by your upper body, the pack employs bungee-like connection points across the chest that can be adjusted from a single point to micro-adjust fit and pull the pack closer to your frame. The soft fabrics and frameless design assure a chafe-free carry and leave your diaphragm able to expand freely so your breathing remains uninhibited. Extensive, wide-open mesh on the backpanel and broad harness straps helps to cushion the pack against your body while maximizing airflow to keep you cool. To ensure that you stay properly hydrated, two included 500 ml soft flasks nestle conveniently in front harness pockets for quick access and easy drinking. There are numerous other front pockets to help organize gear and keep everything close at hand. In addition to the two front flask pockets, there are two other stretch pockets, one front zippered pockets, and one expandable pocket. There is a large main rear compartment and a lower back pocket with side access. An integrated whistle adds a measure of safety and meets the requisite standards of some organized ultra races. The pack is compatible with Salomon's Custom Quiver (sold separately) which offers a convenient solution for carrying foldable trekking poles. Sized to mirror the fit of apparel, the Salomon Sense Pro 5 Set vest pack is available in your choice of color and size options. See the size chart for size recommendations based on your chest measurement.