Philips Lighting MASTER TL-D Super 80 Fluorescent Tubes Philips Lighting MASTER TL-D Super 80 fluorescent tubes are low-pressure mercury discharge T8 lamps. They meet the standard T8 size, and have a 26mm diameter. The special fluorescent coating of MASTER TL-D Super 80 tube lamps ensures excellent color rendering. MASTER TL-D Super 80 fluorescent tubes are a great environmental choice, and offer excellent value compared to TL-D standard lamps as they are far more energy efficient. They also provide more lumens per watt and better color rendering than standard TL-D colors. You can use these fluorescent bulbs within existing TL-D light units.