The Mark IV helmet was used by the United States Navy for many years as part of the Mark IV High Altitude Full Pressure Suit. The main compoinets of the hlemet consisted of a reinforced plastic hard shell, incorporating oxygen breathing, communications, and suspension equipment. An adjustable tinted sun visor was also provided. The Mark IV outfit was used with the Navy high-performance aircraft such as the F-8 Crusader and F-4 Phantom II, when operating above 50,000 feet. It was adopted by the United States Air Force with modifications and designated as the A/P 22S-3 suit. A further development of the suit and helmet was also used by the astronauts in the Mercury space program.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.