Arc'teryx's air permeable Polydel Mesh helps the Women's Sarix Shirt breathe the moment you put it on for mountain training. Most breathable shirts start breathing once you start sweating, while the Sarix stays ventilated and dry before you ever work up a sweat. Designed with Arc'teryx's trim fit, the Sarix includes gusseted underarms that keep the shirt in place while you run. Smooth flatlock seams help prevent chafing, and reflective blazes help with visibility in low light conditions.