SunBlaster T5 HO 18 in 6400K Replacement Lamp (6/Cs) High Output 6,400K lamps simulate natural sunlight and are ideal for cuttings or vegetative growth Some horticulturist's choose 2,700K for budding and blooming SunBlaster's T5 HO lamp produces a light of much greater strength than a conventional tube and, as a result, the energy input into the area being lit is much greater and the light penetration is far superior to anything previously available