Electrolux and the Nilfisk UZ934 Cubit Terrier Vacuum Cleaner pack of 5 exhaust filters.
These are a packet of 5 white rectangular exhaust filters. Probably a filter should be replaced after every second dustbag. They do get very black with carbon from the motor.
At the moment, standard postage is capped at a maximum of $25 within Australia, so maximise the saving on postage and buy something in the related parts below!