S = from 1.10 m to 1.40 m
M = from 1.40 m to 1.70 m
L = Taller than 1.70 m
Bear in mind that these numbers should be interpreted based on your physique. If you're 1.45 m tall with a small head, size S may be better, whereas if you're 1.75 m and have a normal-sized head, choose size M rather than L.