Insulation in Maxi-Cure Dryers

Hi folks,
Does anyone know what the insulation in Maxi-Cure dryers is? I recently picked up a 36-6-3 and it's got a few pieces of insulation that have lost the foil backing which should be acting as a radiant barrier. I'd like to replace those pieces. It looks like standard ductboard, but I wanted to make sure it wasn't something high temp before I went there.