The B flat suspended fourth seventh chord is a 4-note chord consisting of the notes Bb, Eb, F and Ab.
You can see these notes highlighted in the interactive piano chart below.
The chord itself is often abbreviated as Bb7sus4.
Chords that are a superset of Bb7sus4. The chords include more notes but always Bb, Eb, F and Ab.
Chords that are a subset of Bb7sus4. These contain less notes but all of them are included in Bb7sus4.
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 Bb7sus4 chord. Feel free to save or share the image as needed.