Type A-11 intermediate flying helmet, Swiss modified
The official photo on the left shows the helmet with the improved late style donuts containing the ANB-H-1 receivers. It features stud fasteners and hook to attach an oxygen mask, and a dark leather chin strap buckled to the left and buttoned to the right.
It seems that the A-11 was catalogued by the Swiss Fliegertruppe with the white paint / punched holes. It remains uncertain which of the modifications came first. There are specimen which are both painted and punched, (see Swiss NAF 1092), other helmets only have the white finish (see Gfeller), and again others only the holes (see Swiss A-11).
By 1954 the Type A-11 was listed as a winter flying helmet for the North American P-51 Mustang and AT-16 Harvard/Texan.