GermGuardian LB200 UV-C Replacement Bulb is a 1.7-watt bulb. The UV-C light helps reduce airborne bacteria, viruses, mold spores* and works with Titanium Dioxide to reduce volatile organic compounds. *Tested with Staphylococcus Albus, and Escherichia Coli, Aspergillus Niger, and Phi-X174. This bulb needs to be replaced every 10 months depending on use and environmental factors. It can be used for the GermGuardian® model AC225W. The use of this genuine Guardian Technologies™ replacement part will maintain the product's performance.