Enjoy the durability and convenience of our lifetime-guaranteed, custom-made galvanized steel filter frame, complete with 12 polyester filter inserts. Each frame is precisely cut ½ inch shorter on each side than standard hardware store filters, ensuring a perfect fit. For example, a 20x25x1 frame is crafted to a true size of 19.5x24.5x1 for optimal compatibility with your HVAC system.