[COMPATIBLE WITH VARIOUS SLEEP EQUIPMENT MACHINES] - Fits all Respironics M Series, PR System One Series, and SleepEasy machines. Each filter is designed to fit your machine precisely. [PREMIUM CLEANFLOW TECHNOLOGY] - The reusable black foam filter helps block large particulate matter, while the white ultra-fine filter helps capture fine particles. Use them together for improved air filtration. [HELP MAINTAIN MACHINE PERFORMANCE] - These filters help protect your machine by reducing the buildup of dust, dirt, and other particles in the motor. [30-PIECE ECONOMICAL SET] - Includes 15 reusable black foam filters and 15 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 White Ultra-Fine Filters. Note: Light reflection and different displays may cause slight color variations between the image and the actual item. Measurement may vary by +/- 1-3 cm.