Ab 13#11, 1st inversion (B# in the bass)
Also written as Ab13#11/B#.
Notes, from the bass up
B# (bass)D#F#A#DE#G#
The same notes as Ab 13#11 (B#, D#, F#, A#, D, E# and G#), rearranged so B# is the lowest note. Use it to move between chords with smaller jumps across the keyboard.