Herbie Hancock on Flexi Disc

It's as thin as a piece of paper and they call the Flexi Disc, also known as a Phonosheet or Soundsheet. According to Wikipedia it is "a phonograph record made of a thin, flexible vinyl sheet with a molded-in spiral stylus groove, and is designed to be playable on a normal phonograph turntable...It is used as a means to include sound with printed material such as magazines and music instruction books...and [it] was very popular among kids and teenagers and mass-produced by the state publisher in the Soviet government."

Found on the November 8, 1973 issue of Down Beat, Herbie Hancock Demonstrates The Rhodes Piano is a flexi disc (7") featured with the journal. A track from the disc can be heard here: