The A sharp sixth chord is a 4-note chord consisting of the notes A#, C##, E# and F##.
You can see these notes highlighted in the interactive piano chart below.
The chord itself is often abbreviated as A#6.
Chords that are a superset of A#6. The chords include more notes but always A#, C##, E# and F##.
Chords that are a subset of A#6. These contain less notes but all of them are included in A#6.
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 A#6 chord. Feel free to save or share the image as needed.