Very rare 2N393 PNP Germanium transistor in a TO-24 metal test tube. Made by Sprague. Awaiting datasheet. Status: NOS (New Old Stock) circa 1960's NSN: 5961-00-778-3814 indicates these were used in the Polaris Nuclear ICBM (Inter Continental Balistic Missile), not so re-assuring postscript : The Polaris upgrade probably now uses all surface mount components, "allegedly" leftovers from the Xbox 360 parts bins (*). ..... Blue ring of death anybody ? NB: (*) This is a joke, everyone knows the parts come from the later Xbox One as the missiles have to have the capability to self power up if someone shouts "on" , just don't shout "fire" Update 23-1-2017 ...... Polaris missile fails test launch and heads towards to USA, Oooops.... that's an own goal !