Heavy Duty Disposable 23-1/2"x21"x1" Pleated Filter. This disposable filter provides efficient filtering against air particles and debris. This Heavy Duty Disposable Pleated Filter is easy to replace. This Filter is ideal for keeping residential and even commercial grade systems clean and healthy. Be sure to replace your filter every 80-90 days to avoid any malfunctions that come with a clogged and dirty filter. This pleated filter is just one of the many amazing products that you can purchase from PlumbersStock.com, which is the perfect place to shop when looking to complete any residential or commercial project.