
Check the Resmed CPAP machines for the number of filters. Some have two, and others might have one. The major role of filters is to block the dirt and dust particles from entering inside the machine, right from where you inhale.
This episode is also available as a blog post: https://citycpap.wordpress.com/2020/09/26/easy-method-to-clean-your-resmed-cpap-machines/