High strength, good toughness, not easy to break, they are suitable for students' physics teaching. Simply turn the handle and then the electricity generated makes the bulb light. Great for classroom physics teaching demonstrations. The hand crank generator is a great gift for students and children to learn physic science. The outer casing is made of plastic, which can intuitively understand the principle structure of gear transmission. With it, by building science experiments, improving their hands-on ability, thinking ability, creativity., Weight: 0.2976240537 pounds, Manufacturer: Ehwisbe