Hat block 22.5 inches (57.15 cm) with a vent Material: Balsa wood In English, it's called "free form," and in Japanese hat schools, it's referred to as "te-gagen" (a technique of shaping by hand). It perfectly replicates the shape of a Westerner's head, and because the material is soft, it's used with a technique of shaping while inserting pins. There are some pin marks remaining, but they do not affect the creation process at all. Purchased from the English hat block maker, Guy Morse Brown. https://www.hatblocks.co.uk/product/cloche-bundle-3/