American Air Filter PerfectPleat® HC M8 – 18″ x 20″ x 1″ – High Capacity Pleated Filter – MERV 8. American Air Filters PerfectPleat® HC M8 filters are designed with a MERV 8 rating initially but increase efficiency when dust loading begins. Using DuraFlex® media made from uniform size virgin fibers, the pleated panels are self-supporting. With 25% more media than American Air Filter standard capacity filters, the American Air Filters PerfecPleat® HC M8 filter is ideal when higher performance is required. As an enviromentally friendly product, the PerfectPleat® HC M8 filters do not require wire for support, making them completely incinerable.