Abstract: A filter adapter for engaging a filter to fit the filter into a vacuum cleaner chamber. The filter adapter includes an adapter ring having an inner ring perimeter and an outer ring perimeter, and a number of protrusions extending from the outer perimeter of the ring. Alternatively, there is provided an adapter ring and filter assembly for use in a vacuum cleaner chamber. The assembly includes a filter having an outer filter perimeter, and an adapter ring having an inner ring perimeter configured to surround the outer filter perimeter and an outer ring perimeter configured to contact an inner surface of the vacuum cleaner chamber.