CPAP mask cushions are the part of a CPAP (Continuous Positive Airway Pressure) mask that forms a seal around the nose or nose and mouth. They are typically made of silicone or gel and are designed to provide a comfortable and secure fit. The cushion needs to be replaced periodically as they can become worn or lose their shape over time. Some people may also need to change the size of the cushion to ensure a proper fit. It is important to choose a cushion that is comfortable and fits well to ensure the effectiveness of the therapy.