This is a foot petal switch used in tattoo machines, sewing machines, and many other industrial machines. Great for accepting inputs from foot taps! It is actually a SPDT switch and has 3 output wires - Common, Normally Open and Normallyl Closed. There is an electrical connection between Common and Normally Closed wires when the switch is not press. When the switch is pressed, there is an electrical connection between Common and Normally Closed Wires.
You can connect the switch to a microcontroller to accept and read inputs. You can also connect loads upto 240C 10A directly through the switch. Great for turning on/off motors, solenoid vavles, etc