The item presented here is a beautiful Morion style helmet used by the Swiss Guard in service to the Pope in the 1960s.
It has full plumage.
In nearly 20 years of searching for papal items this is the only time I’ve seen one of these helmets available.
The white plume along with the red felt interior indicate the helmet was made for the commanding officer. This is the most ornate form of Swiss Guard helmet and was reserved for use at only the most important occasions.
The coat of arms is from the della Rovere Pope, Julius II, who established the Swiss Guard. –Father Richard Kunst
Both the first and second pictures of the helmet clearly reveal the coat of arms in the embossing.
A morion helmet is a type of open helmet used from the middle 16th and early 17th centuries, usually having a flat brim and a crest from front to back. It has been represented in 19th and 20th century book illustrations and in films as well as by the Vatican Swiss Guard.