The Best Downhill Mountain Bike Helmet of 2021
18.9-20.9inches or 20.9-22.8 inches head circumference. Weight: 0.9 Pounds. This mountain bike helmet is available in two sizes, the first size has 18.9 to 20.8 inches circumference, and the second size has 20.9 to 22.8 inches circumference. It is one of the lightest but also reliable helmets of all-time.