The F4 Plus Model is a 36 GPM point-of-entry system for medium to high flow applications that renders chlorine-resistant parasites, bacteria and viruses harmless. This system features a UV sensor for system performance feedback, an EOL timer that tells you when to replace the lamp, an LED status monitor to track system functionality and stainless steel chamber. For the current rebranded version, please see the VIQUA F4+. *UVMax F4 Plus has been renamed VIQUA F4 Plus. Replacement parts available below.