GeneralAire Filters Part No. 14201 and 4501. Nominal size is 20 x 25 x 5. Actual size is (H) 19 5/8 x (W) 24 3/8 x (D) 4 3/4. GeneralAire has started rounding the dimensions on their 5 filters. These filters still fit the same; they just no longer contain fractions in the description. Pre-applied gasketing on the assembled filter prevents air by-pass. It has 98% efficient filtration media. High-efficiency filter media collects small dust particles before they can collect on your coils. Superior frame strength utilizing double-wall construction and die-cut fingers. No assembly combs needed...filter just slides right in! Each filter is individually bagged. Use the bag to dispose of the old filter!