Germicidal lamps efficiently emit a large amount of ultraviolet rays 253.7nm (nanometers) which have excellent germicidal effect. These lamps have structures and electrical characteristics similar to those of general fluorescent lamps used for illumination but use ultraviolet ray glass which efficiently transmits ultraviolet rays at 253.7nm. 
This wavelength is in the region of maximum germicidal effectiveness and is highly lethal to virus, 
bacteria, protozoa and mold.

The lamps are primarily useful for sterilization of air, the surfaces of various materials and water or liquid in laboratories, food processing industries and for disinfecting water supplies.