5.57 oz., 92% recylced polyester, 8% elastane; Moisture-wicking; UV resistant 40+ UPF; Four-way stretch; Three-button placket; Flat Knit Collar; MATTR (Materials, Technology & Research) is the performance fabric designed for the highest level of comfort no matter the climate condition; Bluesign certified style that utilizes bluesign approved fabrics and materials that are safe for the environment, safe for factory workers and safe for the consumer.