- bass guitars
- electric guitars
Sergio Santucci, developed a 10 stringed instrument called the Treblebass which combines the range of the electric guitar and bass. The instruments were made in Japan and distributed by Santucci Corp. of New York.
Watch this - your mind will be blown: https://youtu.be/H4-EYfUXDOk
Source: Santucci Treblebass catalog 1990.