I am a college professor specialized in environmental crop physiology. We purchased commercial-grade growth light from other companies before, which cost way over $1k per piece and a lot of them had quality issues and eventually the brightness fade off over time. Gave this light a try and used a scientific-grade PAR (photosynthetic active radiation) sensor and realized that this unit can put out about 1200 to 1300 µmol m-2 s-1 on full power, which is more powerful than our $1k light, which only gives 700 µmol m-2 s-1. Just to put in perspective, 1200-1500 is almost full-sun condition outdoor. I need to find out how long they can last, but as of now, cannot be more happier.