GMAX® is excited to introduce the ALL NEW AT-21S designed competitively from the ground up. The AT-21S is constructed from a lightweight Polycarbonate shell offering superior protection and exceeds DOT and ECE safety certifications. This helmet is made in 3 shell sizes, from youth to adult, offering a lightweight shell for any adventure. Internally, the helmet is equipped with an inner sun shield, SpaSoft™ interior and recessed speaker pockets for communication systems. The removable interior with COOLMAX® CORE Technology wicks moisture away from the body and is designed to keep you dry and comfortable during your journey. Enjoy your adventure with the all new AT-21S from GMAX®.
Gmax Helmet Sizing Chart
Helmet Size | Centimeter | Hat Size | Inches |
XS | 54cm - 55 cm | 6-3/4” | 21-1/4” - 21-5/8” |
Small | 56 cm - 57 cm | 7” - 7-1/8” | 22” - 22-7/16” |
Medium | 58 cm - 59 cm | 7-1/4” - 7-3/8” | 22-13/16” - 23-1/4” |
Large | 60 cm - 61 cm | 7-1/2” - 7-5/8” | 23-5/8” - 24" |
X Large | 62 cm - 63 cm | 7-3/4” - 7-7/8” | 24-3/8” - 24-13/16” |
XX Large | 64 cm - 65 cm | 8” - 8-1/8” | 25-3/16” - 25-5/8” |
XXX-Large | 66 cm - 67 cm | 8-1/4” - 8-3/8” | 26” - 26-3/8” |