The GeneralAire 13428 is the correct replacement for the following air cleaner:
The GeneralAire 13428 Filter End Sealer Kit, also known as part number 4025, includes paper end seal part number 13405 and 13406. This cabinet replacement seal kit is the fiberglass looking material that is glued to the back of the metal cabinet, as well as the back door of your GeneralAire AC4 Air Cleaner. To install this item you will need to purchase spray glue, which is sold separately.
GeneralAire Filter End Sealer Kit specifications:
The GeneralAire AC4 is a whole house air cleaner that should be installed in the return air duct system of an office or home. This air cleaner is mounted to the inlet air side of a furnace or air handler. If you only have a heating system, replace your air filter media every 12 months. If you have heating and air conditioning, replace your filter every 6 months.