Eb 13sus4, 3rd inversion (C# in the bass)
Also written as Eb13sus4/C#.
Notes, from the bass up
C# (bass)E#B#D#G#A#
The same notes as Eb 13sus4 (C#, E#, B#, D#, G# and A#), rearranged so C# is the lowest note. Use it to move between chords with smaller jumps across the keyboard.