Klim ECE Men's F4 Motocross Motorcycle Helmet - Circuit/X-Large Air Induction System Supports Air-Craving Intakes To Deliver Substantial Air-Flow And Volume Into Ventilation System Eps Air Channels Continuously Introduce Fresh Air To Inner Pressure Chamber Network And Transport Heated Air And Excess Moisture To Exit Ports Large, Effective Exit Ports Moisture-Wicking Comfort Liner And Cheek Pads Integrates With Ventilation System And Enhances Cooling Via Airflow Perforations INCLUDED WINDSTOPPER LINER IS SMALL AND POCKETABLE, SNAPS ONTO FOAM COMFORT LINER TO PROVIDE WINDPROOF WARMTH WHILE STILL MAINTAINING INCREDIBLE BREATHABILITY AND MOISTURE REMOVAL