An internally insulated exhaust aftertreatment device with a converter body, an end cone assembly and a sealing device inserted in an annular area between the external shell and the substrate of the converter body. The sealing device is sealingly engaged between an inner end cone and the insulating material. The sealing device comprises a wire-mesh ring-shaped device conformable to the annulus between the substrate and the shell, and may have a substantially round cross-sectional area, a C-shaped cross-sectional area, or an L-shaped cross-sectional area.