All heating sections are constructed with totally enclosed, fin tubular elements. With heating section installed, unit becomes a 24V control unit and can utilize low voltage thermostat for control of heating. For 72" through 120" units, order multiple heater modules corresponding to the actual air curtain models used. 48" in length. 240 volts. 12000 watts. Modules are Non-Returnable. UL Listed. 1 Year Limited Warranty.