MIGRO 400+. Hi, the bulb will generate 80% of its original output after 20,000 hours or about 5 years continuous growing. Shane Torpey - 12th August 2019. 315W CMH Economy (incl. Full Spectrum bulb) Hi, this light is a good solution for a 4ft x 2ft space and will cover from 3 to 5 plants depending on size.