What should you pay attention to?
To measure the circumference of your head, run a tape measure around your head above your eyebrows, over your temples.
Open and enlarge the helmet to its largest setting and position the helmet on the head so that the front edge of the helmet is one finger width above the eyebrows. Slide the front and back sections of the helmet together until a comfortable, snug fit is achieved. Now tighten the adjustment mechanism.
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