As in the description - Size is approx: Medium (7 – 7 3/4), circumference = 21 7/8 – 23 1/2" (56 – 60 cm), but may fit slightly larger. We only have it in the one size

Depends on the size of the kid, how old, what size is thier head ? ITs Approximately 7 1/4" in diameter (Medium fit) for an adult or teenager perhaps.