Also known by ET as 150 The advantage of the Exo Terra Repti Glo Compact Fluorescent bulb is its size and the fact that it is self-ballasted. A regular screw fitting is sufficient to operate these bulbs. The spiral shape of the bulb enables vertical or horizontal mounting without compromising performance. It is recommended to combine a high UVB output (Repti Glo 5.0 and 10.0) with a very high visual light output (Repti Glo 2.0) for optimal results. Fluorescent bulbs do not provide sufficient heat. A separate heat source is required in addition (ex: incandescent basking lamp). The Exo Terra Repti Glo 10.0 has a very high UVB output similar to that associated with desert environments. Desert locations receive more direct sunlight than any other because of fewer clouds, less air humidity and no plants or trees to provide shade. Therefore desert reptiles are more exposed to UV radiation than any other type of reptile. This bulb can also be used on screened terrariums or terrariums with dense screen covers to ensure UVB penetration. Dense screens can filter out up to 50% of the UVB rays.