Blue-Tube UV - The Original Low-Voltage Ultraviolet (UV) Light Kit with Odor Sanitizing Technology. The Fresh-Aire UV light included with Blue-Tube UV reduces mold, odors and other microbial growth inside the air system. This allows the system to operate more efficiently while saving energy and money. Blue-Tube UV also sterilizes airborne biological contaminants (viruses, bacteria, mold, and allergens) in the home. Air is continuously cleaned by repeatedly passing by the disinfecting light while cycling through your central air system.