The best built, best performing Merv 11 one inch pleated air filter available. Purafilter 2000 Gold series contains up to 25% more filter media than any other Merv 11. Last three months and beyond. Visit our website for more information. Purafilter 2000 Gold Series proudly utilizes Intrepid 411 SF Premium Filtering Meda. Industrial strength two-piece bonded die-cut construction. Free reminder service with our exclusive Purafilter 2000 assurance program. The Gold Series combines our exceptional Purafilter 2000 quality and value with Intrepid 411 SF high performance media.