X-lite X-551 Sécurité Et Instructions D'utilisation page 21

TOP VENTILATION SYSTEM (FIG. 19)
The two top air intakes allow conveying air into the shell, independently from the VPS
position:
A) closed
B) open
REAR EXTRACTOR (FIG. 20)
The rear extractor ensures optimal heat dissipation.
LOWER VENTILATION SYSTEM (FIG. 21)
The chin guard ventilation system is controlled by two flaps:
A) closed
B) open
21