The Viqua 602805 UltraViolet Lamp is a replacement bulb for the Viqua D4 D4+ D4-V and D4-V+ systems and discontinued Trojan C C4 and C4-V systems. This bulb provides protection from occasional intrusion by microbial contaminants eliminating up to 99% of protozoan cysts bacteria and viruses. During ultraviolet sterilization water is exposed at a controlled rate to UV light waves which deactivate the DNA of microorganisms and prevent them from reproducing. Easy to install and maintain with replacement needed every 12 months. Order the 602805 Viqua Water Disinfection System UV Lamp today!