I made this adapter because my Air Conditioner filter size is 22x24 which is a really oddball size. there are 20 inch and 24 inch filters but almost no one makes (and even less stores carry) 22inch sizes. This adapter lets me (and you) use a 20 inch filter and takes up the slack for the extra 2 inches. You can use several on each side or just one side depending on how much you need. Because of the build size limitations of most printers you will need at least 2 per side. They fit snugly on the filter and are a great way to use smaller filters if you cant find the size you need.! The design is also easy to resize, as you can make them longer or deeper and just resize the entire model and it will sill work.Since you don't need this to go the entire length of your filter, and since there will be a very small gap between this piece and the filter, I recommend using blue tape to get a good seal the length of the filter.