The Key Pleat Air Filter is a standard capacity pleated filter, available in 1", 2" or 4" depths and several standard face sizes to accommodate most system requirements. A seven-strap die cut is located on the air-leaving side of the Key Pleat MERV 8 providing additional strength and durability to each filter. The inside of the die cut frame is coated with adhesive to ensure a solid bond at all points of contact with the media pack. The pack is sealed inside the frame and pleat tips are bonded to the stabilizers and diagonal support members. ** Facts about home and business air filters, Allergies, and filter quality: When looking to replace your air filter, there are typically two different sizes you need to understand, "Actual Size and Nominal Size". First: The Actual Size consists of the true dimensions of your filter when measuring height, width, and Depth (thickness). These dimensions typically include a fraction of an inch within them. For example: 19 1/2 x 19 1/2 x 3/4 Second: What you might not realize is that filters are not sold by their actual dimensions. Instead, a rounded up number is used to label filter packages. This measurement is referred to as the "Nominal Size". So a filter with actual dimensions of 19-1/2”H x 19-1/2”W x 3/4"D will have a nominal size of 20”H x 20”W x 1"D, and that will be the measurement to look for when buying your replacement filters