Major and 7th chords are arranged on the upper row, and Minor, Diminished and Augmented chords are arranged on the lower row. Each row has 24 chords (24 major chords on the upper row and 24 minor chords on the lower row) and each chord has 2 bass notes which are an octave apart. The BCH-48 new non-valved, single reed model has the ability to add your own bass notes to a chord providing strength of tone and fullness of sound. When accompanying another harmonica player, you have the effect of a trio ensemble! Supplied with a beautiful velvet lined hard case with gig bag and carrying strap to protect your harmonica.