The Craftsman Ash Vac Drum Filter prevents cold, dry ash and debris from escaping the drum for easy cleanup. The combination of the Ash Vac Drum Filter and the HEPA Media Filter (CMXZVBE38740, sold separately) provide two levels of filtration where the HEPA Media Filter captures fine dust and debris, while the Ash Vac Drum Filter prevents that debris from escaping into the air. The Craftsman Ash Vac Drum Filter only fits the Craftsman Grill and Ash Vac (CMXEVBE17050, sold separately) and must be used with the HEPA Media Filter. The black lip of the Ash Vac Drum Filter creates a suction seal, containing debris within the drum. With this dual filtration, you can continue to keep your grills, pizza ovens, indoor and outdoor fireplaces, and other spaces clean of cold, dry ash and debris. Do not use the Ash Vac Drum Filter or the Ash Vac for wet pickups. The Ash Vac Drum Filter is washable and reusable, just air-dry the drum filter as needed. If you notice any rips or tears in the Ash Vac Drum Filter, do not use it and replace it immediately.