LEDs are an alternative to bulbs and are useful for adding colour to models. The 5mm LEDs require a 2.5V power supply and are sold 25/pkg. 5 x RED, GREEN, BLUE, YELLOW, WHITE There is a right and a wrong way to connect the legs. You will notice that one leg is longer than the other and the longer leg should be connected to the + (positive) rail or end of the battery. The shorter leg is connected to the – (negative) side. 25/pkg