The TriOx ultralow NOx gas burner uses a three-staged air injection design for maximum production efficiency while minimizing NOx emissions-as low as 20 ppm or less-even with high-temperature preheated air. The burner is capable of low excess air operation (5%) throughout its entire operating range, resulting in outstanding fuel efficiency. It is suitable for processes in excess of 1600 F (870 C) including aluminum furnaces, steel reheat furnaces, thermal fluid heaters and other high-temperature heat-processes requiring ultralow NOx emissions. The burner can operate with a 10:1 ratio on turndown. The burner produces a visible, scannable pilot flame throughout its entire operating range, even when operating in the Invisiflame(tm) mode.