DOT Full Face Motorcycle sports Bike Helmet 508_122 Pink (Large) XS __ 52 - 53 _____ 20 1/4" - 20 7/8" SM __ 54 - 55 _____ 21" - 21 5/8" MD __ 56 - 57 _____ 21 3/4"- 22 3/8" LG __ 58 - 59 _____ 22 1/2" - 23 X-Large __ 60 - 61 _____ 23 1/4" - 24"