★★★Attention ，if you don’t know which size is right for you， please compare with the following date. ★★★<br />American  Size6   diameter 16.5mm   perimeter 52mm<br />American  Size7   diameter 17.3mm   perimeter 54mm<br />American  Size8   diameter 18.2mm   perimeter 57mm<br />American  Size9   diameter 19mm   perimeter 60mm<br />American  Size10   diameter 19.8mm   perimeter 62mm<br />American  size11   diameter 20.7mm   perimeter 66mm<br />American  size12   diameter 21.5mm   perimeter 70mm