18 months & up. When kids click together these chunky pieces and then flip the switch, they'll get an exciting result: either a spinning fan, a glowing light, or a whistling siren. All switch blocks are interchangeable for mixing, matching, and experimenting with actual working circuits in a completely safe way. Young children will develop an innate understanding of circuitry and build a strong foundation for future STEM success with these early childhood science tools. Includes: Light, Sound, and Fan Action Tops, Slide, Rocker, and Button Switch Blocks, Instructions, and Parents Guide. Requires 6 AA batteries (not included).