.... that allows electronic access to Metheny's Synclavier and hence to all its synthesized sound effects. The 6-string section can be played normally also. The rest of this thing is what's called a "harp" guitar that has open fretless strings, so it can make all kinds of sounds like Indian sitars and stuff like that. So in most of these videos, I think what looks like fretting is just Metheny adding the ancillary sound effects while actually playing the rest of the strings.