Designed with a filtering medium that is continuous filament spun glass, it keeps furnaces and air conditioners clean and running efficiently. It is effective against dust, debris and lint. The frame is made with one continuous piece of chipboard to guard against corner separation. Optimize this filter by changing it monthly during high-use periods; one case will last you a year.

• Lasts up to 30 days
• Change filters monthly for peak energy efficiency
• Low airflow resistance
• UL class II
• Self-retaining media adheres directly to the cardboard frame