3M Speedglas G5-01 Directives D'utilisation page 35

b. While holding the airduct tube holder ring together, push it through the rectangular hole in the back of the shroud (Fig. 29b).
Fig. 29b
c. Reattach the airduct tube holder to the head suspension. You will hear an audible "click" when appropriately connected (Fig. 29c and 29d).
Fig. 29c Fig. 29d
33