Congratulations Gabe and Philippe, superb and rare M06 test helmets. Gabe's indeed has his original tip replaced by a standard M87, and the 4 holes for the folding lugs are still clearly visible.
In 50 years of collecting in Metz, I've acquired 4 or 5 KIR145 helmets, but never an M06 Versuchshelme. I don't despair...
With their hinged neck cover, optional front vent, and B.A.0. type tip, I think this was a test for hot countries, such as Macedonia, the Balkans, China, Cameroon, etc.