AprilAire #401 Filter Replacement Media THUMD200ABM00BA but their tests are done

but their tests are done at 300 feet/minute

Lennox Healthy Climate X8309 Expandable Filter MERV 10

as to flammability Class 2

• 9V Battery Backup – Provides continuous protection in case of a power failure

AprilAire #401 Filter Replacement Media THUMD200ABM00BA but their tests are done#401 Media for Aprilaire Space Gard Models 2400 Air Cleaners These are the original, OEM expandable "accordian" style, factory recommended replacement filters for the Aprilaire Space Gard Model 2400 Air Cleaner. The filters ship like a collapsed accordian and are expanded into a plastic frame within the air cleaner cabinet. The filter is installed within the plastic frame and held in place with your existing pleat spacers(NOT INCLUDED). Assembly