4 Pack Vacuum Cleaner HEPA Filters for Cyclonic Series RO3753EA RO3731EA RO3786EA [COMPATIBLE & PERFECT FIT WITH VARIOUS SLEEP EQUIPMENT MACHINES]- Fits for All Philips Respironics M Series, for PR System One Series, for SleepEasy Machine! Each filter to fit your machine precisely.<br> [PREMIUM QUALITY CLEANFLOW TECHNOLGY]- The reusable black foam filter is to block large particulate matter, the white ultra fine filter is to block fine particles. Use them together to provide the cleanest air.<br> [KEEP YOUR MACHINE RUNNING LONGER AND MORE EFFICIENTLY]- Not Only Do Our Filters Help Keep Your Lungs Clean, But It Also Prevents Dust, Dirt, and Other Buildups from Entering Your Motor.<br> [30 PCS ECONOMICAL SET]- Include 15 Pcs Reusable Black Foam Filters and 15 Pcs White Ultra Fine Filters, replace your filter every two weeks is recommended.<br> Colour: black + white<br> Material: sponge + cotton<br> Package Contents:<br> 15 * Reusable Black Foam Filters<br> 15 * White Ultra Fine Filters<br> Only the above package content, other products are not included.<br> 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.