The Philips Respironics Dreamstation comes with a reusable dark blue reusable pollen filter which is washable and should be kept clean on a regular basis.
There is also an optional disposable ultrafine filter which is placed over the top of the washable filter.
This dark blue washable filter will last for a long time and the disposable filter is not washable and should be replaced monthly to protect the washable filter and the machine
The filters are located under the flap on the right hand side of the machine