Holding Tank Heater - Our holding tank heating element is an easy and practical way to winterize your RV or Trailers` tanks. They can be used on either fresh or septic tanks. It is dual voltage ready for both 12-volt and 110-volt applications. These elements are thermostatically controlled and activate at approximately 34­ Fahrenheit to stop the contents of your tank from freezing. The element is 30in x 13in and is a foil covered heater. It comes with a 24in ground wire for safety 6` of 120-volt wiring for easy installation. Each heater draws approximately 1-Amp A.C. and 10-Amps D.C. current when in use. Multiple elements can be used where needed for tank coverage.