M-Series Reusable Black Filter
This is the reusable foam M-Series filter from Respironics that fits in all M-Series machines. Although reusable, Respironics recommends that these filters are cleaned at least once every two weeks and replaced twice a year.
When replacing the filters, put the filter into the machine first with the mesh side facing into the machine. Then, insert the black filter on top of the new white filter.
For the Respironics M-Series User Guide, please click here.