X-Small measures 5 1/2"L x 4 1/2"W Small measures 7"L x 5 1/2"W
Medium measures 7 1/2"L x 6"W
Large measures 8"L x 6 1/2"W
Hats and Caps: For proper fit, measure the length of head from ½” above dog’s brow to back of head.