Cbmaj11 chord

The C-flat major eleventh chord (abbreviated Cbmaj11 chord) is a six-note chord consisting of the notes C♭, E♭, G♭, B♭, D♭, and F♭. The chord is formed by adding an eleventh to the C-flat major ninth chord.

In practice, the fifth (G♭) is often omitted from the Cbmaj11 chord to avoid a very dissonant sound, and because it's not always possible to play all notes simultaneously.