"Exciting portable color organ provides a colorful display in response to music. Display shimmers and flashes to your music without any connections. The kit uses 6 jumbo red LEDs and 6 jumbo yellow LEDs with a sensitive amplifier IC. No connection to yourstereo is needed as the Shimmering Color Organ Kit uses a crystal microphone to pick up the sounds of your music! Take your color organ with you anywhere, as it requires only one 9V battery (not included) to operate. Size of board: 2 3/4"" x 3 1/8"". Complete with all parts, PC board and instructions. Skill Level 2. "