Best Lights Patented Super Reflector Technology produces more light per watt than any other light source. Indoor basketball, volleyball, and gym lighting are the most abused. Best Lights makes the most durable Direct and Indirect light fixtures that can take the hit from a basketball, volleyball, soccer ball, dodge ball, football, or tennis ball played in gymnasiums. The T9 Ceramic Discharge Metal Halide (CDM) lamp is not like old Metal Halide. At 115 lumens per watt the lamps last 30,000 hours with minimal light loss. Crisp, white light at 4200 Kelvin with no color shifting has a (CRI) Color Rendering Index of 90+ which makes all the colors pop and seeing the ball easier. The ballast are electronic, silent and have a dimmable option down to 50% light allowing light to illuminate adjacent courts at 50% power. Perfect for lighting all types of indoor sport facilities in conventional buildings or air domes with ceiling 15 to 100 feet high.