Wood Science Experiment Set DIY Assemble Building Puzzle for Children Girl Description: Hands on Ability: Fun trackball assembled toys, exercise children's hands on ability, DIY science toys, models for children's educational technology projects. Nut: The nut bears the weight and controls the direction of the track. Track: Ramp track, glass ball rolls smoothly. Fence Board: Comes with a storage box to avoid the loss of glass balls; Gasket: A gasket is attached to the bottom, anti slip and anti scratch. Educational Learning Toy: Suitable for school project, DIY science, mental school students, kids, children. Specification: Material: Wooden Size Chart: Assembled Size: 20x16.5x7cm/7.87x6.50x2.76inch Package includes: 1 Set DIY Science Kit Model Trackball Toys (The Received Goods Are in Loose Pieces and Need to Be Assembled Manually by Yourself)