A slide switch, just as its name implies, is to slide the switch bar to connect or break the circuit, and further switch circuits. The common-used types are SPDT, SPTT, DPDT, DPTT etc. The slide switch is commonly used in low-voltage circuit. It has the features of flexibility and stability, and applies in electric instruments and electric toys widely. How it works: Set the middle pin as the fixed one. When you pull the slide to the left, the two pins on the left are connected; when you pull it to the right, the two pins on the right are connected. Thus, it works as a switch connecting or disconnecting circuits. See the figure below:
The circuit symbol of the slide switch is shown as below. The pin2 in the figure refers to the middle pin.
2.16 Slide Switch (Arduino Project)