This is a set of three Centuri A5.2 rocket motors packaged for retail sale. They are made of pasteboard and contain non-explosive propellant. The "A5.2" signifies that they are in the second lowest class (out of seven) of motor power as established by the National Association of Rocketry. Each motor is used only once to power a model rocket. Although the igniters are supposed to be included in the package, for unknown reasons they are missing. G. Harry Stine, a pioneer in the field of flying rocket models, donated this artifact to NASM in 1973.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.