A 6 pack of disposable ultra-fine filters for the Philips Respironics DreamStation 2 series of CPAP machines. The ultra-fine filter has the blue plastic frame. (The pollen filter has a gray plastic frame.)
The brand of filter you receive may be Philips or it may be a third-party filter manufacturer, depending upon availability from Philips.
The DreamStation 2 was initially released in Spring 2021.