Toysmith X-Stream inches Glider #74900 (Colors May Vary) These gliders capture the energy wasted by conventional wings Air passes through the unique wing configuration nearly all of the energy is used and creates the phenomenon that we call inches Dynamic Natural Propulsion inches Dynamic Natural Propulsion also works in water by converting buoyancy to thrust 9 inches Glider Fun For Ages and up These gliders capture the energy wasted by conventional wings Air passes through the unique wing configuration nearly all of the energy is used and creates the phenomenon that we call inches Dynamic Natural Propulsion inches Dynamic Natural Propulsion also works in water by converting buoyancy to thrust 9 inches Glider Fun For Ages and up