Feature: 1. Children can learn some scientific knowledge while playing, expand scientific knowledge and promote children's intellectual development. 2. It can cultivate children's operation ability and logical theories through disassembly and assembly. 3. It can also help them think, increase creativity and interest in learning, hand‑eye coordination and concentration. 4. Made of high quality plastic material, safe, non‑toxic, and comfortable without worrying about scratches. 5. Can be used as an educational and experimental tool in the classroom to enhance fun. A great gift for children. Specification: Item Type: Experimental Kit Material: Plastic Color: As shown in the picture Assembly Size: Approx. 18.5x17x8cm / 7.3x6.7x3.1in Weight: Approx.115g/4.1oz Applicable Age: Over 5 years old Ability Development: Intellectual development Experiment Type: Physics . Package List: 2 x Base2 x Conveyor Belt2 x Connecting Rod4 x Half Moon2 x Backlight Hemisphere2 x Long Axle2 x Short Axle2 x Belt Pulley2 x Paperboard Note: 1. Please allow 1‑2in error due to manual measurement. Thanks for your understanding.2. Monitors are not calibrated same, item color displayed in photos may be showing slightly different from the real object. Please take the real one as standard.