Wowsa! // The electromechanical implants were nothing short of an engineering marvel. The highly miniaturized series of circuits were stuffed into a metal bar that ran the length of the typewriter, making them invisible to the naked eye. The implant, which could only be seen using X-ray equipment, recorded the precise location of the little ball Selectric typewriters used to imprint a character on paper. With the exception of spaces, tabs, hyphens, and backspaces, the tiny devices had the ability to record every key press and transmit it back to Soviet spies in real time. //

Wowsa! // The electromechanical implants were nothing short of an engineering marvel. The highly miniaturized series of circuits were stuffed into a metal bar that ran the length of the typewriter, making them invisible to the naked eye. The implant, which could only be seen using X-ray equipment, recorded the precise location of the little ball Selectric typewriters used to imprint a character on paper. With the exception of spaces, tabs, hyphens, and backspaces, the tiny devices had the ability to record every key press and transmit it back to Soviet spies in real time. //
http://arstechnica.com/security/2015/10/how-soviets-used-ibm-selectric-keyloggers-to-spy-on-us-diplomats/