Bbmaj11 chord

The B-flat major eleventh chord (abbreviated Bbmaj11 chord) is a six-note chord consisting of the notes B♭, D, F, A, C, and E♭. The chord is formed by adding an eleventh to the B-flat major ninth chord.

In practice, the fifth (F) is often omitted from the Bbmaj11 chord to avoid a very dissonant sound, and because it's not always possible to play all notes simultaneously.