Nilfisk and Electrolux Euroclean UZ934 Cubit and Terrier commercial vacuum cleaner exhaust filter grill. This exhaust grill is on the top, but at the back of the machine.
Filter Part Number 140-6879-500 is placed under the grill to collect the carbon from the motor brushes. These are in packets of 5 and are found below in the related parts.
As it's light, maximise the saving on postage & buy a couple of replacement filters, dust bags, or some accessories such as a new floor tool or round brush or even a hose! See in related parts below.
At the moment, standard postage within Australia is capped at a maximum of $20!