The G sharp diminished seventh chord is a 4-note chord consisting of the notes G#, B, D and F.
You can see these notes highlighted in the interactive piano chart below.
The chord itself is often abbreviated as G#dim7.
Chords that are a subset of G#dim7. These contain less notes but all of them are included in G#dim7.
In case you prefer a non-interactive variant of the chord chart, we've embedded a PNG image below that shows the notes for the the G#dim7 chord. Feel free to save or share the image as needed.