This is a rare instrument. The mandobass is like an orchestral double bass / upright bass. It is tuned E, A, D, G and has only single strings. Most folk and traditional bands (or mando orchestras) tend to use electric basses or orchestral basses instead of the mandobass. It has a wonderful sound and the frets help give it a brighter, richer sustain over a (typically fretless) orchestral / jazz style upright bass.