The name doesnt lie: Built with a sheer, performance fabric, engineered with perforation for airflow, the Marmot Mens Windshear Long Sleeve Shirt allows for hyper breathability. Whether youre planning on walking to the pub or picking up the trailhead on the outskirts of town, this packable piece has mechanical stretch, gusseted underarms and solid good looks. Fabric is 100% polyester plain weave stretch 3.4 oz.yd. AirExchange performance fabric. Packable, air permeable, lightweight fabric. Ultraviolet Protection Factor UPF 20. Polyester for quick drying and wicking. Mechnical stretch for added comfort. Gusset for range of movement. Contrast inside collar stand. Shirt tail hem. Single patch pocket. Regular fit. Avg. wt. 7.05 oz. 199.9g.