For use with all Devilbiss IntelliPAP 2 CPAP machines: These reusable pollen filters come 2 per pack. Foam pollen filters are an essential component to your CPAP therapy due to their ability to remove dust and pollen particles from the air. Compatible Machine: DeVilbiss IntelliPAP 2 Auto CPAPThe Foam filter should be checked every 10 days and cleaned as necessary. The filter is located in the rear of the device behind the filter cover. Replace the foam filter every 6 months or sooner if it is damaged. The Foam filter is designed to filter particles larger than 3.0 microns in size. The IntelliPAP 2 MUST have the Foam filter in place during operation.