Yarn and needles:

Size large: Head circumference 22.5 inches or larger. Approximately 90 yards of sport weight or heavier single and 25 yards of extreme lamb’s tail or any art yarn that is about the same weight. US 11 circular and double pointed.

Size small: Head circumference up to 22 inches. Approximately 70 yards of sport weight or heavier single and 20 yards of extreme lamb’s tail.
US 10.5 circular and double pointed needles.