Description: 【Science Experiment Material Set】: Science experiment kits help students enhance their scientific knowledge.The small person pushing the mill utilizes the principle of leverage. When person pushes the grinding disc, it actually forms a lever between the wheel axle of the grinding disc and the long rod of the pushing mill. The long rod of the grinding disc exerts a downward force at the touch point with the grinding disc, while the grinding disc exerts an upward reaction force through the bearing 【Unfinished】: Puzzle kits for kids, which need to be assembled by yourself to exercise children's hands on ability, thinking ability, and fine motor skills 【Materials】: Science experiment stem project are made of wooden materials. 【Interaction】: Building kits, parents can make and assemble them with their children, cultivating their interest in science and enhancing the relationship between both parties 【Gift】: Wooden 3d puzzles are early education gifts for children, promoting interest and creativity Specification: Material: Wood Size Chart: 12.5cmx7.5cmx12.5cm/4.92inchx2.95inchx4.92inch Package Includes: 1 Wooden Science Experiment Model Kits Note: 1.This is not infant toy, please take away from children to avoid eating. 2.Please allow slightly errors due to manual measurement and different monitors.