The Philips DreamStation 2 Auot CPAP Advanced uses a grey reusable pollen filter that can be rinsed and a blue disposable ultra-fine filter. The reusable filter screens out normal household dust and pollens, while the ultra-fine filter provides more complete filtration of very fine particles. The reusable filter must be in place at all times when the device is operating. The ultra-fine filter is recommended for people who are sensitive to tobacco smoke or other small particles.
The grey reusable filter is supplied with the device. A disposable blue ultra-fine filter may also be included. If a filter is not installed when you receive your device, you must at least install the reusable filter before using the device.