These are three unflown Model Products Corporation Minijet rocket motors. The motors are made of pasteboard and contain non-explosive propellant. They are from the same production lot of the motors used at the first National Association of Rocketry Miniroc contest in 1971. Each motor is used only once to power a model rocket. G. Harry Stine, a pioneer in the field of flying rocket models, donated them 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.