The 507s ergonomic fit is a melding of the classic 504 cap & the fit of a baseball. Made using a seamless knitted blocked wool fabric. The Seamless Wool 507 presents the original 507 cap without the seamed side panels. Shape- Ivy Caps & Flat Caps. Fabrication- Wool Felt. Material- 70% Wool / 30% Modacrylic. Brim- 1 3/4 inch peak. Lining- Unlined. Crown- Blocked. Season- Autumn/Winter.