These amazing marble-runs are ideal for the techno-mad dad or any mechanically-minded person! Hours of absorbing fun are guaranteed as they assemble these cleverly-crafted, ingenious power-driven puzzles. Hypnotic in it's appeal, this hi-tech marble run will amuse, delight and enthrall children of all ages! Each set features over a hundred parts to assemble, motor-powered chain drives, 8 marbles plus comprehensive instructions to build your marble dream machine! They are challenging and fun to build and suit all ages over 8. Batteries for the sets not included.