Heavy Duty Disposable 12"x25"x1" Filter. This disposable filter provides protection against air debris and particles that can aggravate seasonal allergies for 2-3 months. This Heavy Duty Disposable 12"x25"x1" 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.