Like a smoothed-out Catlike Whisper, the Zirion relies on a quantity of small vent holes over larger slit vents. It works, pulling in fresh air and moving it through the helmet for effective cooling.
The internal shape is good, enveloping the head and sitting low over the temple and ears. The rear retention strap is low enough to hold on tight, though adjustment is stiff and not as precise as some, and the full in-mould construction makes it easy to wipe clean and less susceptible to damage.
For the weight and price, the Zirion is a bargain.