Features: Hand crank generator motors set will not hurt your child's hands, making it safe to play. This hand generator motor assemble kits can improve children's hands-on abilityand guide children to understand scientific principles. Our physical experiment kits enhances the promotes thinking skills. Creative physical model offer a fun and educational way to explore the wonder of science. This Assembling science toy is guaranteed to spark curiosity and inspire a love of science for students. Specifications: Component: Metal, Plastic Package Size: about 13x17cm/5.12x6.69'' Package Includes: 1 Set Hand Crank Generator Motor Kits note: Please allow 1-3cm errors due to manual measurement. Due to the difference betweeen different monitors,the picture may not reflect the actual color of the item.