Hat block 23 inches (58.42 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-kagen" (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 Guy Morse Brown, a hat block maker in the UK. https://www.hatblocks.co.uk/product/cloche-bundle-3/