A switch is a switch, and an LED is an LED, but this LED illuminated button is a lovely combination of both! It's a medium sized button, large enough to press easily but not too big that it gets in the way of your project panel. It has a built in LED that can be controlled separately from the switch action - either to indicate or just to look good.The body is a black plastic with the LED built inside. There are two contacts for the button and two contacts for the LED, one marked + and one -. The forward voltage of the LED is about 3V so connect a 220 to 1000 ohm resistor...