Sequencer (Stepper) Toe Piston

The console's combination action, capture system, or piston system provided by the builder allows the player to bring on or retire pre-programmed stop and coupler combinations simply by pushing a single piston button with a thumb or a single toe piston with a toe.
NOTE: Toe pistons (photo) are located just above the pedal keys to be easily accessible by the organist's foot.
The so-called general piston sequencer, sometimes called a stepper piston, is a relatively new device that allows the player to move through a pre-programmed sequence of general piston combos, either up or down, by repeatedly pushing the same centrally-located toe piston (labeled "Seq" in photo).
This can save time (and anxiety) by avoiding a search for the desired general toe piston or general thumb piston when a registration change for the entire organ is called for -- a feature much appreciated by organists and, when present, much used to move quickly and smoothly from one layer of sound to the very next one.
Its operation simply requires the foot to always find just one place above the pedal keys where the stepper piston is located -- either to the left or right of the row of swell shoes -- which can be "memorized" and blindly returned to by the foot, time after time.
Two more pistons labeled " + " (plus) and " - " (minus) are provided which command the direction the stepper piston is to move, upward or downward, each time it's depressed.
Many older consoles which have been recently rebuilt and electrified have been retrofit with this feature, and, as expected, its presence opens up a whole new dimension of control for the organist.