Bieffe Helmet Size Chart

Inches	Helmet
20 1/4	X-Small
20 7/8	X-Small
21	Small
21 5/8	Small
21 3/4	Medium
22 3/8	Medium
22 1/2	Large
23 1/4	X-Large
24	X-Large
24 1/8	XX-Large
24 7/8	XX-Large