Oxygen Concentrator filter consists of a plastic housing and an internal fiberglass pleated element. These filters are not washable and only need to be replaced regularly. The purpose of this filter is to clean the air before it enters the compressor directly and to reduce the noise generated when the machine is working. The more dirt the filter blocks from the compressor, the longer the compressor will last longer. Our filters are tested according to the method specified in Appendix A of ISO14644-1:2015, and the filtered gas meets the ISO5 of air cleanliness standard.