BTW, Jason is correct in that most of these bulbs share a manufacturer. The major manufacturers are Iwasaki, GE, Sylvania, BLV/Ushio and Venture and most private brand bulbs are made by one of the companies though there are some small outfits in Asia that make bulbs of mediocre quality (in my opinion). Usually these bulbs are an off the shelf lamp branded for the manufacturer. What you are seeing with the new mid Kelvin lamps is an effort by aquarium lighting manufacturers to work together with a major manufacturer to produce a bulb with a specific purpose. Usually to find a median between intensity and coloration. The fixture manufacturer generally develops the formulation and sets the specs and owns the rights to the lamp if it is there formula but one of the big manufacturers makes it.