20x30x1, Percisionaire Ez Flow Merv 3, 10155.012030, Pack12 20 x 30 x 1 in. EZ Flow Spun Fiberglass Disposable Furnace Filter. Flat Panel&#44; Metal Retainer On Air Exit Side. Only Up To MERV Rating 4&#44; 30 Day Filter. Effective Against Dust&#47;Lint. Pack of 12.