Pack of 12 disposable UL Class II rated air filters designed for protection of furnace and central air units;MERV 4 rating: Removes household dust, pollen, and lint;Continuous chipboard design guards against corner separation while the one-sided metal media retainer adds to the filter strength;Each filter maintains efficiency for up to 30 days;Compatible with HVAC systems requiring filters sized 21 x 21 x 1

• E-Z Flow Air Filter, MERV 4, 21 x 21 x 1-Inch,
• 21" x 21" x 1"/12 Pack

E-Z Flow Air Filter, MERV 4, 21 x 21 x 1-Inch,Flanders Corporation