piano chord
B♭7sus4
B♭1E♭4F5A♭♭7
A dominant seventh with the fourth standing in for the third.
Written the other way round it is A♯7sus4 — the same twelve keys on a piano, a different piece of notation.
What is true of it
B♭7sus4 is B♭, E♭, F and A♭ — 1, 4, 5 and b7 counted from B♭.
On an instrument that cannot reach all 4, the 5 goes first, in that order.