Mega-Ray Externally Ballasted Metal Halide Bulbs are a great choice for reptiles that like high-intensity light, this product requires an external ballast to produce a high-intensity burst of electricity to ignite the chemicals and begin to emit light. The 150W bulb is a great choice for a bearded dragon in a small 200 to 400l enclosure it is also useful to use as part of a multi-light-source setup in a larger enclosure when a distance from the surface of the bulb to the top of your reptiles is approx 55cm.