Aviation obstruction marking sphere is designed to provide daytime visual warning or nighttime visual warning if comes with reflective tape, for electricity transmission line and overhead wire for aircraft pilots, especially cross river high voltage transmission lines. RedDot OMARK power line marker ball is made of high- grade Fiberglass Reinforced Plastics(FRP), diameter of 600mm and 800mm are available to meet different customers’ needs. A marking sphere should be of one color such as aviation orange, white and red. Generally, the marking spheres are placed on the highest line. Where there is more than one line at the highest level, white and red, or white and orange spheres should be displayed alternately. This alternating color scheme provides the best conspicuity against all background.