This is the Photoflex StarLite CoolStar 150 Fluorescent Lamp. It is the brightest CFL (Compact Fluorescent Lamp) available for photographic lighting. It is color balanced to 5600°K, allowing daylight balanced shooting.
Cool light operation allows for continuous lighting while using economical strobe-designed soft boxes. Its brightness is equivalent to 450-500W tungsten light, 8000 Lumens.
Fits the Starlite QL, StarLite 3200 and Constellation3 light heads, or almost any brand of fixture that accepts mogul-base bulbs