Features & details • PROTECTION AGAINST VIRUSES, BACTERIA, AND CYSTS. Our top-of-the-line Ultra systems with Clearsource-exclusive VirusGuard filters that use NASA-developed technology to remove or reduce not just bacteria and cysts, but viruses. No other RV water filter on the market provides anything close to that level of protection. • VIRUSGUARD VS. 0.2 MICRON FILTERING. Our exclusive VirusGuard technology traps even the smallest viruses using an electrically charged coating. 0.2 micron filters are effective only against rare, larger size viruses and allow the vast majority to pass. Unless rated "absolute" like those in our Premier systems, only some of the pores are the rated size and do not provide even the limited protection claimed. • THREE-STAGE FILTERING. Our top-of-the-line Ultra water filter system filters your water three separate times. Our 5-micron filter removes or reduces rust and sediment. Our 0.5-micron coconut shell carbon block filter improves taste, and removes or reduces chlorine, volatile organic compounds, and other contaminants. Our third stage VirusGuard filter removes or reduces bacteria like e. coli, cysts like Giardia, and - unique to Clearsource - all types of viruses. • BULLETPROOF CONSTRUCTION. We build our Ultra systems with a rugged, industry-exclusive powder-coated metal chassis and stainless steel fittings. • REPLACEMENT FILTERS AVAILABLE ON AMAZON. Genuine Clearsource Replacement Filter Three Pack With VirusGuard available on Amazon!