Controls in the console which connect together the various keyboards, so that while playing upon one, the stops drawn upon another also sound (INTER-couplers, e.g. Swell to Great); or transferring the played keys upward or downward an octave on the same keyboard to increase the range or shift the register of the stops drawn (INTRA-couplers, e.g. Swell to Swell 4′). Couplers permit the greatest possible number of combinations of stops and, in effect, extend the reach of the organist’s hands and feet.