Bell Volt RL Road Bicycle Helmet. It's not just the number of air vents 22 that gives the Belt Volt RL Bicycle Helmet its cool, comfortable feel on the road. It's the design of those vents. They pull in cool air as you ride, directing it through the internal StreamJet ventilation channels and over your head. The rear exhaust ports pull out the warm air, creating a consistent cooling effect. Overall comfort is further enhanced via the Twin Axis Gear TAG fit system and Cam Lock levers, which make for quick and precise strap adjustment.