High strength, good toughness, not easy to break, they are suitable for students' physics teaching. The outer casing is made of plastic, which can intuitively understand the principle structure of gear transmission. The hand crank generator is a great gift for students and children to learn physic science. Simply turn the handle and then the electricity generated makes the bulb light. Great for classroom physics teaching demonstrations. With it, by building science experiments, improving their hands-on ability, thinking ability, creativity. Do you want a scientific experimental tool? This hand crank generator be your . Suitable for students DIY scientific experiments. It is excellent to develop their practical ability and thinking ability. Size:13.50X10.00X4.00cm/5.31X3.93X1.57in No-load output voltage:6.3V Output current:0.2A Colour:Transparent Blue Material:plastic Package Contents: 1 * Hand Held Generator Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.