DIY Assembly Physical Learning Kits: Waterwheel Experiment Come with unassembled parts and instruction: assemble the experiment by yourself Work Theory: Lever principle and gear transmission. Trains children& 39;s hands & eyes coordination, fine motor skills, stimulate observation & thinking abilities Great & interesting physical educational toy, also good for parent-child interactive game Material: Plastic Color: As picture show Specification: Assembled Size: Approx. 17.7 x 10.3 x 8.3 cm / 6.97 x 4.06 x 3.27 inch Package Includes: 1 DIY Waterwheel Experiment Kit (Includes Chinese Manual) : Due to the difference between different monitors, the picture may not reflect the actual color of the item. Due to manual measurement,there may be 1-2mm error in size.