The Whirlpool W11391715 is a disposable grease filter made exclusively for Whirlpool over-the-range microwaves. It sits behind the vent and collects fat and airborne particles produced during cooking. These particles can leave stains on your walls and cabinets, as well as have an impact on indoor air quality. The filter captures them and keeps them from circulating back into the kitchen. By replacing the W11391715 on a regular basis, you can keep your microwave clean, enhance your kitchen's air quality, and reduce the chance of grease stains. Replacing the grease filter is usually a straightforward procedure that does not require any instruments. For exact directions, consult your microwave's handbook still the filter is typically located beneath the vent grill.