Compatible with All M Series, PR System One Series, and SleepEasy machines. Each filter is designed to fit your machine precisely. Premium quality CleanFlow technology: The reusable black foam filter helps block particulate matter, while the disposable white ultra-fine filter captures fine particles. Using them together helps deliver cleaner air. Helps keep your machine running longer and more efficiently. These filters not only help protect your respiratory health but also help prevent dust, dirt, and debris from entering the motor. 30-piece economical set includes 15 reusable black foam filters and 15 disposable white ultra-fine filters. Replacement every two weeks is recommended. Color: Black + White Material: Sponge + Cotton Package Contents: 15 × Reusable Black Foam Filters 15 × Disposable White Ultra-Fine Filters Note: Only the items listed above are included. Light reflection and differences in display screens may cause slight variations in color between the image and the actual item. Measurement error allowed is +/- 1-3 cm.