Broan FILTERSQUARE Replacement Non-Ducted Charcoal Filter for RM51000, RM52000 and RM53000 Series Range Hoods Replacement charcoal filters for use with the RM51000, RM52000 and RM53000 Series hoods when installing hood as non-ducted operation; one required for replacement Used in conjunction with the RRK51 Non-Ducted Recirculation Kit