inlet 142 should be generally equal to or less than about 0 03 inches while each of tubes 130 are about 1 to about 3 inches in length for high reactive fuel such as hydrogen fuel and have generally about 1 to about 8 fuel injection inlets 142 for low reactive fuel such as natural gas each of the tubes 130 can be as long as about one foot in length multiple fuel injection inlets 142 i e about 2 to about 8 fuel injection inlets with low pressure drop is also contemplated with the stated parameters it has been found that a fuel injection inlet 142 having an angle z of about 50 to about 60 degrees works well to achieve the desired mixing and target nox emissions it will be appreciated by one skilled in the art that a number of different combinations of the above can be used to achieve the desired mixing and target nox emissions for instance when there are a plurality of fuel injection inlets 142 in a single tube 130 some injection inlets may have differing injection angles z as shown in fig6 that e g vary as a function of the recession distance r as another example the injection angles z may vary as a function of the diameter d f.