Fangrui Product Details [ Compatibility]designed For Seamless Use With Most Cpap And Bipap Machines, This Filter Kit Fits Perfectly With 22mm Tubing And 25mm Mask Elbows. Each Filter Ensures A Snug Fit, Enhancing Your Devices Performance Without The Need For Complex Adjustments. [optimal Airflow Maintenance]constructed With Advanced Hydrophobic Materials, Our Cpap Filters Promote High Filtration Efficiency While Maintaining Robust Airflow. This Design Ensures That You Receive Clean, Uninterrupted Throughout Your Sleep Therapy Sessions. [installation Simplicity]our Cpap Filters Are Crafted For Easy Setup Without Needing Recalibration. Attach The Filter Between Your Machines Air Outlet And The Tubing, Power Up, And Enjoy A Consistent Flow Of Purified Air, Enhancing Your Sleep Quality Effortlessly. [maintenance Reminder]to Maintain Optimal Performance Of Your Cpap/bipap Machines, It Is Advised To The Filter Every 4-6 Weeks Depending On Usage And Environmental Conditions. This Pack Includes 9 Individually Sealed Filt