DustFighter 90 Electro Static Lifetime filter, washable and reusable, you'll never need to buy another one, just wash this every month or so with a vacuum and a hose and its good as new. We got a new furnace and a different size so this doesn't fit but it still works great. Only a couple years old, the aluminum frame measures 29-5/8" x 27-5/8" x 1". Compare to $125 -150 new - $35 OBO