The A19BAG special thermostat for portable heaters is a single pole, single-throw control with contacts opening on a rise in temperature. The thermostats are supplied with an adjustable range and a fixed differential. A "No Heat" position on the dial permits manual shutdown of the heater without disconnecting the thermostat or the power supply. A special 3-wire extension cord and "series plug" are an integral part of this control to permit "plugging" the heater cord into the thermostat extension cord for automatic operation. A beaded chain hanger is supplied to permit supporting the thermostat in any convenient location.