Method for measuring hat size:

Leather Flight Helmet

Helmet Sizing
Size         

Hat Size              

Head Measurement      
S
6 3/4 - 6 7/8
19 - 20"
M
7 - 7 1/8
21 - 22"
L
7 1/4 - 7 1/2
23 - 24"
XL
7 1/2 - 7 7/8
25 - 26"
XXL
7 3/4 - 8
27 - 28"