Ab Quartal (So What), 1st inversion (C# in the bass)
Also written as Ab quartal/C#.
Notes, from the bass up
C# (bass)F#A#D#G#
The same notes as Ab Quartal (So What) (C#, F#, A#, D# and G#), rearranged so C# is the lowest note. Use it to move between chords with smaller jumps across the keyboard.