For those finding it difficult to get Vacuum filters for Opolar 2-in-1 vaccum plus duster from this deal (https://www.ozbargain.com.au/node/636494).
It is possible Opolar is rebranding a generic vacuum duster sold on Aliexpress and similar websites. They seem to all look the same as the Opolar branded one. Anyways Opolar will not sell replacement filters for this. Only replacement I could find is this. Hope this helps.
It's a shame these cannot be sourced from Opolar directly. Opolar seem to be using a rebranded version of the TAD05 vacuum duster which is on aliexpress. Enjoy
Link to the filters . https://www.aliexpress.com/item/1005002401711066.html