Air switches and air bush buttons are used to control electrical devices without having a live circuit near the spa water. Air push buttons and switches are commonly used on spa baths, hot tubs and older spas. They are very simplistic.
Air switches are not to be confused with the air push button which is the user interface, the air switch is actually the control (switch) hooked directly to the device that is being controlled.
As an example, an air push button sits at the edge of the spa bath. It has a small plastic hose that runs from the bottom of it to the air switch. The air switch can be housed in an air switch box or in the device itself.
When the air button is pushed, the bellows inside of it pressurizes air which in turn pressurizes the bellows in the air switch and that bellows activates the switch. The switch turns a pump, blower or lights on accordingly.
Air switch boxes can have timers and can control multiple circuits with one push button.