Sun Blaster CFL Bulb 200wuse 6400K for growth & 2700K for budding or flowering stages, when used in horticultural applications. Use the 200 watt compact fluorescent bulbs to replace your existing 300 400 watt bulbs, wherever you want to provide full spectrum 6400 Kelvin cool natural light which is comparable to natural daylight. These self ballasted lamps work well in horticultural applications or as warehouse, shop , or barn lighting. Almost anywhere you need bright,