F dim7
The F dim7 chord consists of the F (Perfect unison), Ab (Minor third), Cb (Diminished fifth) and Ebb (Major sixth) notes.

How to play the F dim7 chord
- Find F (Root) on the piano keyboard
- Add Ab (Minor third) — 3 semitones above F
- Add Cb (Diminished fifth) — 6 semitones above F
- Add Ebb (Major sixth) — 9 semitones above F
- Press all 4 notes simultaneously to sound the F dim7 chord