F 13sus4, 1st inversion (Bb in the bass)
Also written as F13sus4/Bb.
Notes, from the bass up
Bb (bass)CEbGDF
The same notes as F 13sus4 (Bb, C, Eb, G, D and F), rearranged so Bb is the lowest note. Use it to move between chords with smaller jumps across the keyboard.