GermGuardian EV9LBL UV-C Replacement Bulb is a 9-watt bulb. The UV-C light fights germs, kills airborne bacteria, viruses and mold spores. The light is a safe and natural way to kill germs without the use of chemicals and produces no ozone or chemical sprays. This bulb needs to be replaced every 10-12 months depending on use and environmental factors. It can be used with the GermGuardian Air Sanitizer Models EV9102, REV9102 and GG3000BCA. The use of this genuine Guardian Technologies replacement part will maintain the product's performance.