These daylight balanced (5000-5500K) lamps are an excellent light source, they feature a long life, low operating cost, give off little heat (you can actually touch the lamp while on) and mix well with natural light. The upper lamp is rated at 85 watts, but has the same illuminating power as a 300 watt incandescent lamp, while the lower is 27 watts, equaling a 100 watt incandescent lamp. There are two drawbacks to these lamps. One, is the size/weight, with the 85 watt version being 12" long and 5" diameter; the weight tends to cause the reflector to sag on the light stand. Two, is the output is more diffuse than an incandescent lamp, and the highest wattage rating I have seen is 105 which equals a 400 watt incandescent lamp; both of these make them less suited for use in taking photographs of the finished pieces, but for construction photos they are excellent.