2018FW visvim Aviator Hat. Size: S-M Color: Navy Material: 63% Wool, 37% Linen Brand new, unused. Comes with box. Purchased at FIL and stored without ever wearing. PILOT HAT using Japanese military twill. (Japanese military twill) Japanese military twill expresses the rough, mixed texture and uneven mottled appearance of the material, which was difficult to procure during the war. This material is characterized by a coarse, dry feel and random texture, made by mixing Shetland wool, linen, and British wool.