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