Supra Life fluorescent black light bulbs last up to 5 times longer than standard black light bulbs. The Black Light is designed with a special filtered glass that absorbs most of the filament's light to create a fluorescent glowing effect when directed at objects and materials. Extended life phosphors reduce color shifting, and provide consistent lumen output levels for up to 90% of rated life hours. Black light sources have many uses. They may be employed for decorative and artistic lighting effects, for diagnostic and therapeutic uses in medicine, for the eradication of microorganisms, for the observation or detection of substances tagged with other substances that exhibit a fluorescent effect, for the curing of plastic resins and for attracting insects. Black Light Blue bulbs are similiar to regular black lights but with a filter in the glass to filter out visible light and provide uv light output only.