B 11/G#
The B 11 chord consists of the B (Perfect unison), D# (Major third), F# (Perfect fifth), A (Minor seventh), C# (Major ninth) and E (Perfect eleventh) notes, with G# as the bass note.

How to play the B 11/G# chord
- Play G# as the lowest bass note in the left hand
- Find B (Root) on the piano keyboard
- Add D# (Major third) — 4 semitones above B
- Add F# (Perfect fifth) — 7 semitones above B
- Add A (Minor seventh) — 10 semitones above B
- Add C# (Major ninth) — 14 semitones above B
- Add E (Perfect eleventh) — 17 semitones above B
- Press all 7 notes simultaneously to sound the B 11/G# chord