Circuit board: thickness 1.5mm, length 64mm, width 26mm Power supply voltage: 4-12V DC voltage, the higher the voltage, the brighter the LED will be. The circuit of this kit uses sound to control 10 LED flowing water, which can display the function of CD4017 very intuitively. It is a kit for learning counter, frequency divider, and color light controller. At the same time, the kit has a very good effect, very interesting and practical. Notice: Identification of the positive and negative poles of the microphone (the pin with three wires at the bottom connected to the shell is the negative pole!) Note that the components on the board should be soldered from the smaller size, and then solder the larger ones. Colour:As Shown Material:plastic+metal Package Contents: 10 * Voice activated LED Water Light Kit CD4017