The SKINS A400 Top features Gradient Compression technology that increases oxygen delivery to active muscles while reducing lactic acid build-up to make recovery easier. The 400 Fit is created to help improve your core's control, allowing muscle flexing but with less soreness. Biomechanically placed Memory MX fabric surrounds the spine and scapula for no restriction during arm movements. A hem gripper helps keep the shirt in place throughout exercise. Stretch airflow mesh under arms. SPF 50+ block and moisture management help regulate body temperature. Taped and bonded sleeves are attached without seaming to eliminate possibilities for chafing. 76% nylon/24% spandex. Imported.