feature: Compatibility: The parking heater controller is suitable for cars, trucks, etc., 2V 24V power supply voltage. And there is a manual refueling mode. 12 Volt Blower Motor Switch for Diesel Heater Humanized Design: Humanized design of the knob switch on the climate control panel, use the knob to quickly set the time, and support timing start or stop. Knob switch for heater controller Professional Manufacture: The parking heater controller switch conforms to the standard specifications, strictly follows the factory quality control, professionally manufactured, skilled in technology, reliable in use and stable in performance. parking heater controller Specification: Power supply voltage: DC 12V/24V Accessories: Universal packing list: 1 controller