[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 M series and 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 may extend the life of the machine. [Perfect filter combination] Includes 20 reusable black foam filters and 20 disposable white ultrafine filters. A total of 40 air filters; it is recommended to replace the filter every two weeks. One set can meet your needs for a full year. [Provide clean air] Helps deliver cleaner air to support respiratory health. White filter dimensions: 4.5 x 2.3 cm Black filter dimensions: 4.5 x 2.5 cm Color: Black + White Material: Sponge Package Contents: 20 x White filters 20 x Black filters Note: Light and display settings may cause slight color variations between the image and the actual item. Measurement error allowance is +/- 1-3 cm.