This Travel Tech sportshirt features a unique fabric technology that maintains the optimum microclimate for your body. Named 37.5, it removes moisture at the vapor stage before sweat can form. 37.5 acts like a thermostat by removing moisture when you are hot and retaining warmth when cold. It absorbs and traps odor molecules that are washed away when cleaned. Button-down collar. 75% cotton, 23% 37.5 polyester, 2% elastane. Machine washable. Imported.