CNZ 9 Watt UV Light Bulbs are PL style lamp with G23 base and is a low-pressure hot cathode germicidal ultraviolet (UVC) mercury arc lamps that is most effective tool for eliminating microorganisms such as virus, bacteria, algae, mold and yeast in the air and impurities in water. 9 Watt UV Light Bulbs are sed in air and water purifiers and also used in ponds and aquariums to clean the water and reduce the algae which forms. 9 Watt UV Light Bulbs are rated for 8,000 hours of normal usage. For optimal performance, replace the bulb in your Ultraviolet (UV) device every year even if it continues to light, as over time the bulbs will lose their effective germicidal light spectrum. compatible for all CNZ, JEBAO, SUNSUN, GRECH,