This is a Flexfit structured cap and it comes in two sizes with an elastic band for a bit of stretch. 63% polyester/34% cotton/3% spandex twill

S/M: 21 ¼ - 22 ¾ inches
L/XL: 22 ⅜ - 23 ⅞ inches

Also, it's custom printed, so unfortunately I can't offer returns/exchanges if you order the wrong size.