Abstract: A core element for use in a catalytic converter, especially an electrically heatable catalytic converter, which core element is characterized by a corrugated thin metal strip having metal tabs attached to each end. The tabs are bent along one or more lines normal to the edges of the corrugated thin metal strip. When bent along one line, for example, an angular tab is formed. When the tabs are bent along an infinite number of lines a uniform amount, a circular segment is formed. A catalyst is deposited on one or both surfaces of the corrugated thin metal strips. A central portion of each strip is flat to enable location between the legs of a bifurcated central pin. The central pin with a group of such corrugated thin metal strips is then spirally wound about the central pin to provide a core with overlapped curved tabs defining at least two discrete generally spiral groups of resistance strips electrically isolated from each other.