This is a replacement ultraviolet (UVC) lamp that also produces ozone for extra sterilization power. The model is GPH357T5VH/4 (also crosses to GPH357T5L/4P), T5 tube shape, with a 4-pin base. It's from Caprock and emits ultraviolet light in the germicidal range, perfect for air purifiers, water sterilizers, or surface sanitizing devices. The ozone helps kill odors and microbes in hard-to-reach places. Important: only use in equipment designed for ozone-producing lamps, and follow safety guidelines (don't look directly at the light, allow ventilation). Brand new in packaging. If your old lamp has burned out or lost effectiveness, swapping in this new one will restore your unit's performance. A crucial component for maintaining a clean environment in labs, salons, or homes. Check your device's specs to ensure compatibility before ordering.