This is a late prototype of the Apollo spacesuit that astronauts wore on the surface of the Moon. The suit bears the designation A6-L, meaning that it was the sixth iteration of the spacesuit, one before the final, made by ILC Industries under contract to NASA. It is possible that this spacesuit was used for astronaut training as well as for testing and evaluation.
NASA Johnson Space Center transferred this spacesuit to the museum after the conclusion of the Apollo program.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.