Open Face Motorcycle Scooter Helmet DOT 318_365 Pearl White (LG) XSM 52 - 53 20 1/4" - 20 7/8" 6 1/2 - 6 5/8 SM 54 - 55 21" - 21 5/8" 6 3/4 - 6 7/8 MD 56 - 57 21 3/4"- 22 3/8" 7 - 7 1/8 LG 58 - 59 22 1/2" - 23 1/8" 7 1/4 - 7 3/8 XLg 59- 60 23 1/2"