This round filter is positioned at the top of the cyclonic dirt chamber on Titan T8000 canister vacuums as well as some uprights and canisters with the Kenmore brand name. It is fabric covered foam within a black vinyl seal. Its diameter is 5 1/8" and height 1".
This filter is also known as KC44KDMTZ000 and KC44KEDCZ000.   For similar products see our list of Titan Vacuum Supplies.