[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 can 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 pieces of air filters, recommended to replace every two weeks; one set can last for a full year [Provide clean air] Helps deliver clean air for you and your loved ones to support respiratory health White filter size: 4.5 x 2.3 cm Black filter size: 4.5 x 2.5 cm Color: black + white Material: sponge Package Contents: 20 pcs x white filters 20 pcs x black filters Only the above package content, other products are not included Note: Lighting and display differences may cause slight color variation between the image and the actual item. Measurement error allowed within +/- 1-3 cm