The measure of the diameter, or thickness, of a conductor, metric gauge is used outside of the United States and England, where American Wire Gauge (AWG) and British Standard Gauge (BSG) are used, respectively. In the metric gauge scale, the gauge is 10 times the diameter of the wire in millimeters (mm), so a 50 gauge metric wire would be 5 mm in diameter. Note that AWG is retrogressive, i.e., the larger the number, the thinner the conductor, but metric gauge is progressive. In order to avoid confusion, metric sized wire generally is specified in millimeters rather than metric gauge. See also AWG, BSG, and gauge.