Pathfinders Leonardo da Vinci Premium Aerial Screw (Helicopter Flying Machine) Wood Model Kit We believe in nurturing a child's natural curiosity and that learning can be fun. Designed by a science educator, our Aerial Screw model kit allows you to explore science and history by building one of Leonardo da Vinci's most iconic images. A great build from beginner to advanced (ages 9+), this kit will keep you and your loved ones entertained for 1-3 hours and can be displayed once completed. Quality is important to us, so our models are made from laser-cut wood and not plastic. They have a great finished look, are sturdy and the pieces fit together perfectly We stand behind our product and our reviews speak for themselves. If you have a part that has been mangled (by us, you or your pet), give us a call and a replacement piece will be shipped to you ASAP All of our kits are tested and pass all ASTM standards for safety. We are an environmentally friendly company and use natural, untreated wood, from sustainable forests (forest stewardship wood). We donate 1% of sales to protect and enhance the natural environment.