[High-quality materials] The CPAP filter is made of high-quality materials, which can effectively filter fine particles, dust, and pollen without affecting air circulation. Perfect replacement for CPAP machines. [Wide compatibility] This CPAP filter is suitable for most CPAP machines, including PR System One series. [Provide good protection for your machine] These CPAP filters help prevent dust, dirt, and other fine particles from entering the CPAP machine, which can extend the life of the machine. [Perfect filter combination] 20 reusable black foam filters and 20 disposable white ultrafine filters. Includes a total of 40 pcs air filters. It is recommended to replace the filter every two weeks; one set can meet your needs for a full year. [Provide the cleanest air] Helps keep your lungs healthy and supports respiratory wellness for you and your loved ones. White cotton sheet: 4.5 x 2.3 cm Black cotton sheet: 4.5 x 2.5 cm Color: Black + White Material: Sponge Package Contents: 20 pcs White cotton sheet, 20 pcs Black cotton sheet. Only the above package content is included; other products are not included. Note: Light and different displays may cause the color of the item in the picture to vary slightly from the real thing. Measurement allowance is +/- 1-3 cm.