Perfect pleat HC M8, pleated filter, 1 inch Standard Size, 15 1/2 inch x 24 1/2 inch x 3/4 inch. Designed, developed and patented by AAF, the perfect pleat HC M8 is a product with form and fit unlike any other pleated filter in the marketplace today. The automated and controlled process AAF has developed for the perfect pleat HC M8 eliminates inconsistencies and irregularities in order to provide the filtering efficiency you need and expect. At the core of every perfect pleat HC M8 filter is duraflex, American Air Filter's patented, self-supporting mediameter When pleated, duraflex will hold its shape without the need for wire support characteristic of conventional, pleated filters. That means safer handling, with no risk of nicks or cuts during installation. The absence of wire also means that the filter will not rust and is totally incinerable, which simplifies disposal.