Vintage Open Face Motorcycle Scooter Helmet DOT Star Black/white 170 (M) 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"- 23 7/8"