Product details:

20x24x5 / 20x25x5 GeneralAire 12758 / 4001 Compatible Air Filters (Pre-Assembled) Compatible pleated filter for the OEM part number 12758 (also known as "Product No. 4001"). Actual dimensions of the filters are 19-9/16" X 24-1/16" X 4-3/4" . Designed for use in the GeneralAire AC1 (also known as "AC Series 1") or AC22 (also known as "AC Series 22" or "Product No. 4422") Residential Air Cleaner . Comes pre-assembled all in one piece