The Medtronic 4-074647-00 is a reusable Expiratory Bacterial Filter Vial designed for use with the 840 Ventilator. This product is essential in ensuring the cleanliness and safety of the ventilator by filtering out bacteria during the expiration phase. It is sold in a box containing one unit. This product is designed for durability and long-term use, making it a cost-effective choice for healthcare facilities. Please note that proper cleaning and maintenance are necessary to ensure the effectiveness and longevity of this reusable filter.