Ops-Core FAST® Helmet Sizing & Fitment Guide
A properly fitted helmet is non-negotiable for safety and stability. Follow this guide to determine your correct helmet and chinstrap size using precise measurements.
📏 How to Measure
- Head Circumference: Pull the measuring tape tight around your head, crossing the center of the forehead and the widest part of the back of your head.
- Head & Face Circumference: Measure the vertical circle from the top of the head, down in front of the ears, and under the chin. This determines your Chinstrap size.
【Helmet Specifications】
| Size | Head Circ. (cm) | Head Circ. (in) | US Head Size |
| M | 53 - 56 cm | 20 7/8" - 22" | Up to 7 |
| L | 56 - 59 cm | 22" - 23 1/4" | Up to 7 3/8 |
| XL | 59 - 62 cm | 23 1/4" - 24 3/8" | Up to 7 5/8 |
| XXL | 62 - 64.5 cm | 24 3/8" - 25 3/8" | Up to 8 1/8 |
【Chinstrap Specifications】
| Size | Head & Face (cm) | Head & Face (in) |
| M | 62 - 70 cm | 24.5" - 27.5" |
| L | 66 - 74 cm | 26" - 29" |
| XL | 70 - 77 cm | 27.5" - 30.5" |
| XXL | 74 - 83 cm | 29" - 32.5" |