the bulbs are both red and blue. 60 red and 20 blue leds to each bulb. I was thinking of cfls, but a 42 watt bulb was a little pricey when you buy 6 of them. The power consumption was als0 a factor. The way my trays will be setup is 48x24 inches. I am hoping 3 bulbs will cover each tray. I have to trays on my starting table.