The Minifon P 55 is a miniature wire recording device manufactured since 1955, which was developed to record conversations without being noticed. The mini recorder was a sensation at the beginning of the 1950s—such a small recorder seemed impossible. The P55 recorded sound on steel wire, as audio tape—which had a better quality—could only record for 10% of the time. The minifon was also used for espionage purposes; microphones could be disguised as a wristwatches, pens, or tie pins.