The HP5 is the helmet of choice for racers in a closed car environment for use with an external cooling system (available separately) or with a simple airduct system (not included). The HP5 is compatible with Bell’s carbon side air and top air kits that channel airflow through the helmet’s ventilation system and attach to the helmet with double sided adhesive. The side air kit divides the air inflow evenly to the front vent channels to cool the face and prevent shield fogging and the top air kits (8 hole & 10 hole) direct airflow around the head to cool the driver.