CARRIER 20x25 Old/Defective Electronic Air Cleaner to Filter Size 20 1/4" x 25 3/8" x 5 1/4". Case of 3This Filter Replaces the 2 Cells in the 26 x 25 CARRIER SAS 18 or SS 18 Electronic Air Cleaners Actual Size of Filter is 20 1 4" x 25 3 8" x 5 1 4" To Convert from Electronic Air Cleaner to Media Air Cleaner, you will need to turn Power Switch Off for the Electronic Air Cleaner permanently and remove the 2 Cells, we highly recommend disconnecting electrical power to Air Cleaner using a qualified Technician You may need to remove plastic tab at bottom