This fun adorable educational and eco friendly toy kit inspires the children and their families to learn about the new form of clean and green energy this will also learn to use natural resources as alternative source of energy make 2 different models propeller yacht and propeller racer powerd by rubber band children can experience the joy and achievement with the assembly which can help them to cultivate their innovation and intelligence experience the power generated by these simple but unseal engines while most of every day turbine engines use fuel as power source your propellers will use energy released by basic rubber band . when assembled 24 cm long and 31 cm tall