This is not a guitar!
Even so it is held as a guitar by the performer and the name suggests a link to a guitar, the sound has little to do with a it. It was one of those many inventions to create new sounds during those still analogue times.
Introduced in 1963 and discontinued only two years later, the Guitaret was an invention of Ernst Zacharias, the mind behind other Hohner instruments like the Clavinet, Cembalet and Pianet.
Marketed as an easy-to-play instrument to mimic guitar or banjo, the actual sound sits somewhere between an electric kalimba and electric piano.
The Guitaret is held like a guitar, with the player holding the “neck” or handle to engage the sustain/dampening mechanism. The other hand is used to pluck the 36 metal keys, which barely protrude out of the instrument’s body. The vibration of the plucked keys is then captured by a series of internal pick-ups.
In recent years, the Guitaret has been used on a number of new recordings, perhaps most notably on the soundtrack for The Assassination of Jesse James by the Coward Robert Ford by Nick Cave and Warren Ellis.
http://www.youtube.com/watch?v=Zaj3miIVRZY
http://www.youtube.com/watch?v=Si0m1H2Hmqk