The B-flat power chord (abbreviated "Bb5 chord") is a two-note chord consisting of the notes B♭ and F. The chord is formed by removing the major third from a B-flat major chord.
B-flat power chord
B-flat fifth chord
B♭omit3 B♭(omit3) B♭no3 B♭(no3)
dyad (two-note chord)