"octave couplers", which add the pipes an octave above (super-octave) or below (sub-octave) each note that is played, may operate on one division only (for example, the swell super octave, which adds the octave above what is being played on the swell to itself), or act as a coupler to another keyboard (for example, the swell super-octave to great, which adds to the great manual the ranks of the swell division an octave above what is being played).