The DreamStation Humidifier Lid Seal seals the humidifier water chamber (tank) to the humidifier lid. It must always be in place when your DreamStation Humidifier is in use.
CLEANING & CARE: The DreamStation Flip Lid Seal may be removed and cleaned as necessary when it becomes loose or dirty. For best results, clean by hand with warm water and a mild soap. Once clean the seal should be laid flat to dry completely, out of direct sunlight and/or heat, before reinstallation. Replace the seal as needed whenever it appears damaged or worn. For complete instructions review the documentation that came with your equipment.