The model PB3 is a spring loaded momentary rectangular exit button, with bi-color illumination, mounted on a stainless steel single gang outlet box cover. The model PB3A is alternate action (push-on; push off). Adding "N" to the part #(PB3N, PB3AN) yields mounting on a 1 3/4" narrow stile plate. The NO and NC (DPST) contacts switch when the button is depressed and return when it is released. The switch is UL listed with 3 AMP capacity. Note that the switch type is double pole double throw. Two of the contacts are not factory wired (see drawing below). The reason for this is that all six contacts are rarely required and providing less factory wiring makes for a less crowded hookup. The installer may use these contacts by soldering leads to them.