This very unusual kit emits random pops and random explosions of bright white light when it is in the dark (kit has a CDS cell to sense the absence of light). This kit produces one of the most unusual "out-of-this-world" effects! Features SCR and CDS cell circuitry with 3 bright lamps and a piezoelectric speaker. This easy to build kit creates a spectacular visual and sonic display. It may even cause speculation as to whether or not it was left here by aliens! We built 4 of these kits and put them is a darkened room and the resulting sound and light display was amazing. Size of PC board: 2.9" x 2.4". Operates on two "AA" batteries (not included). Complete with all parts, PC board and instructions. Skill Level 1.