Abstract: An exhaust gas filter and/or a catalytic converter for the removal of harmful constituents from the exhaust gas of an internal combustion engine is provided with a feed duct (6) to a filter or converter unit (1) made from metal materials, which form a unit penetrated by cavities, through which the exhaust gas is conveyed, from compression-moulded wires or fibers as a tangled mass, braiding, knitted fabric or woven cloth or in powder, granular or chip form, and with a delivery duct (7) for the exhaust gas purified by the filter or converter unit (1). The filter or converter unit (1) is also constructed as a heat exchanger unit for the exhaust gas to be cleaned.