Inner Tite Thermal Cut-offs are engineered to disconnect the power to heating systems when room temperature exceeds 165?F. When the heating system shuts off, flow of fuel oil or gas is discontinued eliminating the possibility of heater damage, a fire, or acceleration of an existing fire. Required by law in some states. Inner Tite Thermal Cut-offs are economical, easy to install, and a prudent back-up to existing built-in heating system controls.