I love the fact that The Croft Shetland Yarn has a great deal of stretch. This hat will fit a small- or medium-sized woman’s head, but, because of the nature of the yarn, the hat will probably accommodate a large size as well. (My head is 22 1/2 inches in diameter and the hat fits me well.) This hat works up very quickly, and the final result is functional, as the aran yarn is warm and cozy.