Ultra-Lite Mat Heat Insulating Mat by Thermo-Tec 18" x 24" This heat insulating mat by Thermo-Tec uses innovative thermal conduction technology, developed by Thermo-Tec to accomplish superior heat insulation in a lightweight versatile product. Ultra-Lite Mat Heat Insulating Mats are constructed from a highly textured aluminum composite surface on one side, with a high temp silica felt center and a durable mylar composite facing. The part number for this item is 16540 and it is 12" x 24".