the 21 bar can be re-arranged and new felt cut to make ANY set of chords you might want...but it can do D, F & such right out of the box...( I did re-cut one bar to make an 'E' maj chord...though I seldom use it...)...short of putting out big money for custom models, the 21 bar is about the most versatile.....but ya gotta get an electronic tuner unless your ears are LOTS better than mine.