This filter is located inside of a Panasonic canister behind the vacuum bag. This piece is a frame and filter together. Panasonic filter AMC415-2969 (AMC415-2969).
This filter is very distinct in appearance due to the red frame. Examples of Panasonic canister models that use filter AMC415-2969 replacement:
MC-V9634-00 MC-V9634C-00 MC-V9641-00 MC-V9644-00 MC-V9644-02