Designed by some of Salomon's top notch athletes but presented in an approachable manner for seasoned and inexperienced runners alike, the Active Skin 4 Set is a sleek, streamlined running vest that offers carrying comfort, minimalist storage, freedom of movement, and at-the-ready hydration! Supported by your upper body, the soft, form-fitting pack has a flexible and adjustable connection point across the sternum but otherwise leaves your ribcage free to expand so that breathing remains uninhibited. The shape and placement of the pack body ensures that weight remains consistent with your center of gravity rather than sagging low on your back and causing undue strain and fatigue. The mesh backpanel and broad perforated harness straps help to cushion the pack against your body while maximizing ventilation. To ensure that you stay properly hydrated, the pack includes two 500 ml soft flasks that stow conveniently in dedicated front harness pockets. There are two other front stretch pockets and a secure zippered front pocket. A zippered rear compartment holds larger items and a separate sleeve with a hanging system allows you to use a bladder, but a hydration system is not included. Other features include an integrated key fob, reflectivity, a safety whistle, and connection points that enable you to carry foldable trekking poles (poles not included). The Salomon Active Skin 4 Set vest pack is available in an array of size and color options. See the size chart for size recommendations based on your chest measurement.