The H-3 was the first "hardshell" helmet tested by the Swiss AF.
Delivery of the first specimen took place during the summer of 1952.
The H-3 is formed by an outer hardshell and a cloth inner liner fitted with communications equipment and oxygen mask "snap-on" fittings.
Those (USN) helmets were painted gold because it was found that this colour provides efficient thermal protection against solar radiation. Other colours (except white) have a tendency to make the helmet warm and therefore uncomfortable.
With aging, the H-3 hardshell has a tendency to turn green, due to the presence of (oxidized) copper particles in the paint.
Copper was supposed, due to its high reflectivety to radar pulses, to be of help with the search and rescue of ditched pilots.
Like it was the case with the specimen pictured here, H-3s were modified with stabilising straps connecting the inner liner and outer shell.
More about the H-3 on the Swiss AF 1950 evaluation page.