The mad hatters at Peter Grimm present this traditional flat cap, also known as a driver cap, in a modern brown and rust plaid. Made from sturdy 100% cotton, this hat is a timeless style with hipster flair from the number-one name in men's headwear. SIZING > MD: 7 1/8, 22.4 inches; LG: 7 3/8, 23.3 inches.