JR PRODUCTS HOLDING TANK HEATER - Holding tank heating element is an easy and practical way to winterize your RV tanks. Can be used on either fresh or septic tanks. Dual voltage ready for both 12 volt and 110 volt applications. Elements are thermostatically controlled and activate at approx. 34°F to stop the contents of your tank from freezing. 30" x 13" element is foil-covered heater; comes with a 24" ground wire for safety, 6' of 120 volt wiring for easy installation. Draws approx. 1-amp AC and 10-amps DC current when in use. Heats tanks up to 15 gallon size. Multiple elements can be used where needed. Holding Tank Heater.