EZ Flow II disposable filters are designed for protection of furnace and central air units in residential and light commercial applications. Product Features Include: EZ Flow II disposable filters are designed for protection of furnace and central air units in residential and light commercial applications; Construction of both models is identical except for the media retainer; The EZ Flow II has no media retainer; Instead, the media itself is adhered directly to the frame for non-metallic applications; The frame is made from heavy chipboard in a one-piece design that eliminates corner separation; Sealing is accomplished with a resilient hot-melt adhesive running the full perimeter of the frame on both upstream and downstream sides; UL markings are on each individual filter, UPC marked; Change filters monthly for peak energy efficiency; Low airflow resistance