The C-flat dominant seventh chord (abbreviated "Cb7 chord") is a four-note chord consisting of the notes C♭, E♭, G♭, and B♭♭. The chord is formed by adding a minor seventh to a C-flat major chord.
C-flat dominant seventh chord
C-flat major-minor seventh chord
C♭ E♭ G♭ B♭♭
1 3 5 ♭7
Tetrad (four-note chord)