Official S/M by Top Of The World Acrylic and Wool Construction for a Classic and Vintage Look and Feel One-Fit Sizing (Comfy, Flex Headband Fits Most Adults, Hat Sizes 7 to 7 7/8) Material: Acylic Premium quality fan gear manufactured by American-owned Top of the World. A terrific gift idea. Premium quality fan gear manufactured by American-owned Top of the World. A terrific gift idea.