Bell's Lumen boasts Bell's Fusion In-Mold Microshell for top strength and durability, their GPS fit system and Cam-lock strap levers for a custom fit and feel, and 22 vents with cooling channels so you stay dry and comfortable on every ride.
Small = 51-55cm
Medium = 55-59cm
Large = 59-63cm
Specially designed ventilation channels bring cool air in through the front and over the head while flushing warm air out through the rear ports. These deep, sculpted channels keep air moving whether you're bombing it at 30mph, or huffing it uphill at single-digit speeds.
Bell's Geared Positioning System (GPS) allows you to get the best fit possible and keeps your helmet exactly where you want it. Easy dial control allows one-handed adjustments to be made quickly and safely even while riding.