Aerostar 20 x 25 x 4 Commercial HVAC Filter - Merv 13, Box of 6 Pleated MERV 13 Media Comparable to Filtrate MPR 1500 to 1900 Comparable FPR 10 Designed for Superior Filtration Efficiency Made with electrostatically charged synthetic material that captures 90% of large airborne allergens such as pollen, mold spores, and dust mite debris. Its robust frame construction enhances quality and ensures high durability Improve Indoor Air Quality Protect your family and loved ones with clean indoor air quality at home. Aerostar filters are a simple and cost effective step towards a healthier home environment, free of airborne allergens and particles that can trigger allergy and asthma symptoms. Reduce Cost An Aerostar furnace air filter helps keep your HVAC unit working efficiently by removing dirt and reducing strain on the motor. When your unit runs properly, it consumes less energy, requires less maintenance and will have a longer life. These factors will have an impact on your utility bill and maintenance costs. It is recommended that you change the filter every 12 months during normal conditions but increase frequency during peak seasons when your unit is working the hardest. About Aerostar Air Filters Aerostar filters are manufactured in the USA by Filtration Group, a world-leading manufacturer and supplier of filtration solutions for residential, commercial and industrial applications. The Aerostar brand is known for constantly innovating and improving their technology to help make filtration more efficient, effective and every day. What's in the Box of 6 Aerostar Commercial HVAC Filters Nominal Size: 20 x 25 x 4 Actual Size: 19 1/2" x 24 1/2" x 3 3/4" , Size: 20x25x4, AC and Furnace Air Filters.