A. They have been tested in the laboratory for one year. The light decline phenomenon is not obvious. As there are no electrodes, the two ends of the tube will not become black like the common fluorescent tube which has the electrodes on the double ends. The induction lamps will keep their lumen output and will not depreciate by 20-30% like other fluorescent light sources do after 6 months operation. According to the initial test, light decline ratio of induction lamps is 15-20% after 10-year operation, and as such it will be the most lumen maintaining lamp in the world.