Reading a tightness test gauge is easy. The far left side of the gauge is for "tight" machines. It is colored blue because "tight" machines suggest that a "cold" number which has not appeared recently would provide an advantage. The far-right side of the gauge is for "loose" machines. This side of the gauge is colored red because "hot" numbers which are showing up more frequently than other numbers can provide an advantage. But not all "tight" or "loose" machines are the same. More extreme machines push the needle to the ends of the gauge. Machines that are behaving as expected are towards the middle. The white zone indicates that there is little advantage to be gained by playing special numbers.