FILTRATION: With high filtration efficiency, the MERV 11 Pleated HVAC Furnace air filter effectively capture unwanted air particles to help improve the overall air quality in your home. EASY TO READ AND USE LABEL: With a location on the label to let you easily mark the date you have installed the filler, helps you to know when it is time to replace the air filter. Locate the air flow direction to quickly install the filter into your HVAC system. REPLACEMENT TIME: For optimal performance, replace every 90 days, or sooner if the filter becomes dirty or damaged. DIMENSIONS: The HVAC air filter's normal dimensions are: 20 x 20 x 1 in. Actual filter dimensions: 19.5 x 19.5 x .75 in. CONTENTS: Included in the package are four (4) MERV 11 HVAC filters., Weight: 0.46 pounds, Manufacturer: Filter Monster