[COMPATIBLE & WITH SLEEP EQUIPMENT MACHINES]- Fits for All , for PR System One Series, for SleepEasy Machine! Each filter to fit your machine precisely. [ CLEANFLOW TECHNOLGY]- The reusable black foam filter is to block particulate matter, the disposable white ultra fine filter is to block fine particles. Use together to the cleanest air. [KEEP YOUR MACHINE RUNNING AND MORE EFFICIENTLY]- Not Only Do Filters Help Keep Your Lungs Clean, It Also Prevents Dust, Dirt, and Other Buildups from Entering Your Motor. [30 PCS ECONOMICAL SET]- Include 15 Pcs Reusable Black Foam Filters and 15 Pcs Disposable White Ultra Fine Filters, replace your filter two weeks is recommended. Colour: black + white Material: sponge + cotton Package Contents: 15 * Reusable Black Foam Filters 15 * Disposable White Ultra Fine Filters Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.