These are two small cylindrical weights, one lead and one brass. They were flown as payloads on an unknown flying rocket model at a National Association of Rocketry event in 1959. The manufacturer is unknown. G. Harry Stine, one of the American pioneers in the field of flying rocket models, donated them to the museum in 1973.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.