This is the worse product I purchased in Amazon. Not worth for the money. The actual size is much smaller. It is not 20 X 25 X 4 and I don't consider this is a Merv 12 level air filter. I bought 6 to save the cost since I have 4 furnaces in my house within the main building and my cabana. The cardboard material is not as strong material as you can find in retail store. Poor quality stuff. Very disappointed on this purchase.