Microwatt

From UroWiki

The microwatt is equal to one millionth of a watt, and is the unit of measurement used for ultraviolet wavelength light, which comes in several varieties: UVA ('black light', long waves at 400-315 nanometers), UVB (medium waves at 315-280 nanometers; the primary source of raw vitamin D3 for reptiles, used to help strengthen bones and metabolise food), and UVC ('germicidal', short waves at 280-100 nanometers).