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