The D4 Premium Model is a 12 GPM point-of-entry system for homes that renders chlorine-resistant parasites, bacteria and viruses harmless. This compact system features state of the art UV sensor technology, 2X the UV-C output of standard low-pressure lamp technology, a lamp age indicator, an LED monitor, stainless steel chamber, and 120 AC voltage. The D4 premium system features a state-of-the-art, touch-screen controller that displays lamp life remaining, support contact information and reminds you when to replace the lamp. D4 UV systems are reliable and time-tested for small home (1-2 bathrooms) and light commercial applications.