The Planet Waves C.T.M. takes the highly successful Chordmaster and adds to it a chromatic tuner and metronome. The Chrordmaster section provides you with the most comprehensive library of over 7000 chords all in the palm of your hand. The easy navigation allows you to find any chord simply and quickly. The C.T.M. even has a "lefty mode" for those often ignored left handed guitarists. Combining this with a fully-chromatic tuner and Metronome makes the C.T.M. your all in one essential practice / reference tool.Also includes 2 extra long life batteries, 'besides' the 2 batteries in the box.