Circumference in inches:Size 1 - 27 1/2 - 31 1/2Size 2 - 31 1/2 - 35 1/2Size 3 - 35 1/2 - 39 1/4Size 4 - 39 1/4 - 43 3/4Size 5 - 43 3/4 - 47 1/4Size 6 - 47 1/4 - 51 1/4