Tilley LTM6 airflo it has an open mesh in the crown and lets air in and sweat out.airflo hat are engineered from tilley nylamtium.Comes with a life time guarantee,if it ever wears out,falls apart, shrinks or mildew.Your hat comes with a non-absorbent foam liner in the crown for floatation,anti sweat band to help wick perspiration away from your forehead,adjustable, tuckaway wind cord.EXCELLENT SUN PROTECTION.All tilley hats have the highest certification rating: ultraviolet protection factor [UPF] 50+