Gbmaj13 chord

The G-flat major thirteenth chord (abbreviated Gbmaj13 chord) is a seven-note chord consisting of the notes G♭, B♭, D♭, F, A♭, C♭, and E♭. The chord is formed by adding a thirteenth to the G-flat major eleventh chord.

In practice, the fifth (D♭) and eleventh (C♭) are often omitted from the Gbmaj13 chord to avoid a very dissonant sound, and because it's not always possible to play all notes simultaneously.