This is one of two spare lamps for the Apollo 11 Crewman Optical Alignment Sight flown on the Apollo 11 command module during its historic mission. Stowed in a storage locker for the entire mission, it could have replaced the COAS lamp during the mission if necessary.
The lamp was transferred to the Smithsonian in 1970.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.