The disposable replacement filters are designed specifically to be used with the ResMed AirSense™ 11 CPAP machines. The length, width, and height are specific to these devices and allow the air to be properly filtrated by the machine. The machines pull from the room air when providing the user a positive airway pressure and the filter is the last line of defense for air pollutants.
The filter should be replaced about every month to two months. This will depend on the air quality in your home and or surrounding environment. A dirty or clogged filter can cause the machine to malfunction and in some severe cases cause complete failure. The replacement of the filters monthly also ensures the user is being provided with the best quality of air possible.