20x25x4 MERV 24-1/2 3-3/4 6 Actual x x Size: AC Pack. & 19-1/2 Filters. Furnace 10

Actual Size: 19.5” x 24.5” x 3.75” | Nominal Size: 20 x 25 x 4 MERV 10 Efficiency with MERV 8 Air Flow (.25" W.C.) Electrostatic Air Filters for homes, business, schools, apartments, hotels and industrial Durable and sturdy galvanized metal backing. Made in the USA. For optimal performance, recommended to change at least every 3 months.