AWG    -           American Wire Gauge

SWG    -           Standard Wire Gauge

Taken from Wikipedia:

AWG - "American wire gauge (AWG), also known as the Brown & Sharpe wire gauge, is a standardized wire gauge system used since 1857 predominantly in North America for the diameters of round, solid, nonferrous, electrically conducting wire.

The current British Standard for metallic materials such as wire and sheet is BS 6722:1986, which is a solely metric standard.

Many jump ring suppliers use SWG measurements for their rings.

PLEASE NOTE: We show both measurements to the best of our ability and or to the closest measurement possible.

Since other suppliers may use a different measurement, it is very important to know and to check before ordering rings, if you'd like to match rings from another vendor.
It is also especially important to check what tutorial or instructions you are using for the correct measurements.

AWG 16 gauge is not the same as SWG 16 gauge and you will end up with a much different ring!