New in Box HJC The worlds leader in Helmets Arena CL-X5 Green Size XXS (note: this is the only size I have in this color) Advanced Polycarbonate Composite Shell: Lightweight, superior fit and comfort using advanced CAD technology. “ACS” Advanced Channeling Ventilation System: Full front to back airflow flushes heat and humidity up and out. Bioceramic Nylex® Moisture-wicking Interior: Anti-bacterial, removable and washable. Large Eye Port and Maximum Range Adjustable Visor: For maximum visibility and superior goggle fit. SNELL/DOT Approved MSRP $149.99 My suggestion is to use this HJC sizing chart if you already have an HJC helmet and are familiar with their sizing go with that. If you do not have an HJC helmet I would suggest that you go up to the next size. Email me with any questions. Size   Centimeter         Hat Size              Inches XXS  51-52                6 3/8 -6 1/2             20- 20 1/2 XS     53-54                6 5/8 -6 3/4             20 7/8 - 21 1/4 S        55-56                6 7/8 -7                   21 5/8 -22 M       57-58               7 1/8 -7 1/4              22 1/2 - 22 7/8 L        59-60               7 3/8 -7 1/2              23 1/4 - 23 5/8 XL     61-62               7 5/8 -7 3/4              24 - 24 3/8 XXL  63-64                7 7/8 - 8                   24 3/4 - 25 1/4 XXXL 65-66             8 1/8 - 8 1/4             25 5/8 - 26 Youth S 49-50           6 1/8 - 6 1/4             19 1/4 - 19 3/4 Youth M 51-52          6 3/8 - 6 1/2             20 - 20 1/2 Youth L  53-54          6 5/8 -  6 3/4             20 7/8 - 21 1/4 Youth S/M 49-50      6 1/8 - 6 1/4             19 1/4 - 19 3/4 Youth L/XL 51-52    6 3/8 - 6 1/2              20 - 20 1/2