C dim7/Eb
The C dim7 chord consists of the C (Perfect unison), Eb (Minor third), Gb (Diminished fifth) and Bbb (Major sixth) notes, with Eb as the bass note.

How to play the C dim7/Eb chord
- Play Eb as the lowest bass note in the left hand
- Find C (Root) on the piano keyboard
- Add Eb (Minor third) — 3 semitones above C
- Add Gb (Diminished fifth) — 6 semitones above C
- Add Bbb (Major sixth) — 9 semitones above C
- Press all 5 notes simultaneously to sound the C dim7/Eb chord