A fiendishly difficult instrument to play. It has the scale length of a bass and the range of a piano. It is played with a technique somewhat reminiscent of Eddie Van Halen's famous two-handed tapping, except that the right hand, which plays the bass strings (which are reversed from their normal order on a bass guitar, to make the instrument more symmetrical), is held perpendicular to the instrument. Famous users include Tony Levin, John Myung of Dream Theater, and Trey Gunn.