Aprilaire 4200 Air Cleaner. High efficiency air cleaner for your whole house. Manufactured by Aprilaire Model number 4200 is designed for convenient installation with any type forced air heating/cooling system. Includes battery powered digital display which can be wall mounted or left on top of unit. Display indicates filter condition and can cycle furnace fan to clean home periodicaly. No electricity required, but installation may require minor sheet metal work. MERV 13 rating.