With this soldering kit, two red 5 mm LEDs are controlled to blink alternately. The blinking speed can be individually adjusted for each LED. The "Blinking LEDs" circuit board is great for experimenting, as a soldering practice, or for light functions in model building, such as level crossing signals, etc. Thanks to the detailed colored instructions and the included bending aid for resistors, the "Blinking LEDs" soldering kit is excellent for beginners, newcomers, and advanced users. A standard 9 V battery (not included) serves as the power supply.