The G flat suspended fourth chord is a 3-note chord consisting of the notes Gb, Cb and Db.
You can see these notes highlighted in the interactive piano chart below.
The chord itself is often abbreviated as Gbsus4.
Chords that are a superset of Gbsus4. The chords include more notes but always Gb, Cb and Db.
Chords that are a subset of Gbsus4. These contain less notes but all of them are included in Gbsus4.
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 Gbsus4 chord. Feel free to save or share the image as needed.