Ideal for applications where an open flame or spark-risk is out of the question; the TD405 excels at providing 425,000 BTUs of clean, dry heat. The patented technology uses a diesel power engine to agitate hydraulic oil in flameless, sparkless, low-pressure environment. The oil is heated and circulated, not burned, providing a clean pollution free discharge to the target environment. Safety features are incorporated to protect the investment of your Therm Dynamics heater. All heaters are equipped with multiple shut-off switches that terminate the engine when low pressures or high water temperatures are detected.