This is the info that I found with a little websurfing.

GERMICIDAL BULBS UV-C Bulbs (VIEW ALL GERMICIDAL BULBS) Use these bulbs for: Air & Water Purification Surface & Material Purification

BLACKLIGHT BULBS

Blacklight BLB (UV-A Bulbs) (VIEW BULBS) Use these bulbs for:

Blacklight BLB style bulbs transmit UV light but use a dark filter to absorb visible light.

Special effects; phosphor glow Parties Stage lighting effects Inspections

Blacklight BL (UV-A Bulbs) (VIEW BULBS) Use these bulbs for:

Blacklight BL style bulbs transmit UV light and have a white finish that also transmits visible light.

Photosensitization applications Photochemical reaction applications Insect traps

PHOTOTHERAPY / TEST BULBS UV-B Bulbs (VIEW BULBS) Use these bulbs for: Dermatology phototherapy Tests / Inspections (UV resistance of materials) Scientific Analysis

UV Explanation & Wavelength Specifications

UV-A Bulbs Low-Pressure Mercury Arc Lamps UVA wavelength range: 315nm - 400nm Peak: 352nm or 368nm

UV-B Bulbs Low-Pressure Mercury Arc Lamps UVB wavelength range: 280nm - 360nm Peak: 306nm

UV-C Bulbs Low-Pressure Mercury Arc Lamps Germicidal Peak: 253.7nm Germicidal + Ozone Peaks: 253.7nm / 185nm

WHAT IS ULTRAVIOLET LIGHT?

Ultraviolet light is invisible to the human eye. It is part of the electromagnetic spectrum that lies beyond the purple range of the visible spectrum. The ultraviolet (or UV) spectrum has wavelengths between 100 and 400 nanometers (nm). The UV spectrum is further divided into wavelength ranges named UVA, UVB, UVC:

UVA: sun tanning, testing, inspection, insect traps, stage effects, blacklight, phototherapy* (315-400nm) UVB: sun burning, inspection, analysis, testing, phototherapy* (280-360nm) UVC: germicidal (253.7nm), ozone producing (185nm)

*Phototherapy for treatment of skin diseases uses bulbs emitting in the UVA and UVB spectral range. There is also non-UV phototherapy for treatment of infant jaundice. These bulbs, "bili lights", are low or non-UV emitting fluorescent or halogen sources with strong blue light in the visible spectral range of 425-475nm.

Warning: UV radiation is harmful to skin and eyes.