The PerfectPleat HC M8 filter has more media than our other capacity filters. MERV8 filters should be implemented where pleated filters are currently in use and higher performance is needed. The PerfectPleat HC M8 filter has an initial MERV 8 rating respectively, but the efficiency increases when dust holding begins. PerfectPleat HC M8 filters have distinctive self-supporting characteristics that allow a pleating pattern. This pleating pattern promotes airflow and maximizes dust holding capacity (DHC). Lower pressure drops and higher DHC translate to reductions in energy consumption and operating costs. Our MERV8 filters are made with DuraFlex media, which allows the filter to operate without wire support. The combination of no wire support and DuraFlex media makes our MERV8 air filters resistant to rust and other damage. Our MERV8 filters will last you well into the future.