Bought this on here to try, lived with it for a while and decided it is not for me. This is not really trying to be a double bass - it is essentially an unlined fretless bass with no body mounted on a stand so that it can be played upright.  It is 34" scale length, so takes regular long scale bass strings.  Neck is just 45mm wide at the nut, string spacing at the bridge 17mm.  Piezo pickups are mounted in the saddles of the bridge, one volume knob - treble and bass can be adjusted via trim