Tilley LTM5 Winterised Airflo Slim Sun HatTilley LTM5 Winterised Airflo Slim Sun Hat For the first time ever, weve crafted the ideal winter Airflo hat that is twice as warm as loose down, four times warmer than polyester, yet light, slim and breathable like the original. Reconstructing the LTM5 using Italian Thindown fill, we have achieved the same slim silhouette with enhanced heat trapping ability, also using a taslan nylon shell that looks and feels like cotton with added water repellency