RZ-Vent Plug in black. These plugs cover the RZ-vent scoops on a variety of RZ helmets, and prevent dust and debris from entering the helmet.
Of course, this also means that the cooling air channels for your helmet will be covered, but for rain or dusty conditions this might be the preference of the racer!
Each vent plug sold separately - typically Zamp helmets with these plugs will need (3) to cover the helmet.