3M™ ThermaVolt TvF Calendered Inorganic Insulating Paper Laminate 7 mil(5+2). 3M™ ThermaVolt Calendered Inorganic Insulating Paper Laminate TvF is 3M™ ThermaVolt Insulating Paper bonded to one side of polyester film. Designed for insulating and protecting electrical equipment at high temperatures.