The gauge number refers to the size of the diameter cut-out next to it. The numbers on a wire gauge vary depending on the type of gauge: on a British Standard Wire Gauge (SWG) type they range from 1 to 36, and on an American Wire Gauge (AWG) type from 0 to 36.
Metric or Imperial number
The metric or imperial number can be found on the reverse side of the gauge. A British standard wire gauge it has metric measurements ranging from 0.19mm to 7.62mm. The American wire gauge, on the other hand, has inches on the reverse ranging from 0.005″ to 0.325″.
Precise diameter cut-out
The horizontal gap at the outermost point is the diameter which is referred to by the gauge number. This is where the wire is placed to determine its size.
Circular run-through area
The circular section acts as a run through for wire that is capable of fitting through the gap. It allows the wire to be easily removed after passing through the gap.
Hole
The hole in the wire gauge enables you to hold onto the wire gauge easily by putting your thumb or fingers through.
