This is a high amperage heavy-duty Snap Action, positive feel transbrake, nitrous or line lock button.
Made by Otto Controls, this button comes complete with a stretch cord. Threaded shaft, and locknut that make it very simple to mount on a steering wheel, or any other desired location.
This button was designed for stock eliminator racers who plan on using the 2-step on the brake pedal as per NHRAs new rules. The wires are safely enclosed, and can handle the pounding of a foot.