[COMPATIBLE WITH VARIOUS SLEEP EQUIPMENT MACHINES] - Fits 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 helps capture fine particles. Using them together helps provide cleaner air. [HELP MAINTAIN MACHINE PERFORMANCE] - These filters help keep your device clean by reducing dust, dirt, and other particles from entering the motor, which may help extend the life and efficiency of your machine. [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 x Reusable Black Foam Filters 15 x Disposable White Ultra-Fine Filters Note: Only the items listed above are included. Light reflection and differences in display screens may cause slight variations between the color of the item shown and the actual product. Measurement error allowance: +/- 1-3 cm.