This new and innovative ThermoSeries Baselayer from FootJoy will keep you warm and more importantly allow air to circulate to prevent overheating. The Hex jacquard pattern of the fabrication creates small ridges within the material which sit just off the skin to allow air to keep moving around. This is made with a raglan sleeve construction and golf compression fit to give the golfer the perfect movement during the swing. FootJoy quality, performance and durability as always.