Abstract: A device suitable for use as a catalytic converter for purification of the exhaust gases from an internal combustion engine at continuous operating temperatures in excess of 1600.degree. F. and up to 2500.degree. F. includes a frangible ceramic monolith catalyst element resiliently mounted in a metallic housing. The monolith is wrapped in a thermally insulating layer of ceramic fibers capable of withstanding continuous exposure to temperatures of at least 2000.degree. F. A layer of intumescent material disposed between the housing and the ceramic fiber layer resiliently secures the monolith in the housing. A method of manufacture of such a device is also described.