Also known by ET as 100 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 5.0 has a moderate to high UVB output, similar to that of shady environments such as rain forests and other tropical locations. Reptiles living in these habitats receive less UV radiation because of the many climatological conditions (fairly high humidity, changes in weather, etc) that prevent direct sunlight from reaching them or their basking sites.