Filter King 20x16x4 MERV 11 air filters are built with a durable, moisture-resistant paperboard frame and pleated, standard-capacity 4-inch media to help your HVAC system run smoothly. Each filter is designed to last up to 90 days under typical residential conditions, capturing everyday airborne particles to support cleaner, healthier indoor air. The actual size of this filter is 19.5x15.5x3.75 inches, so be sure to measure your existing filter carefully to confirm the right fit. For easy comparison, the MERV 11 rating is roughly equivalent to MPR 1200 and FPR 7, making it simple to match performance across different rating systems. MERV 11 offers enhanced filtration for families who want a step up in protection. In addition to capturing dust, pollen, mold, dust mites, bacteria and pet dander, it also helps reduce smoke and smog particles from traffic or nearby industry. It is a solid option for allergy-prone homes that still want good airflow and system efficiency.