Rounak Round Wire Gauges, Range : 0.1-22mm

Round Wire Gauge is a set of wire sizes given by BS 3737:1964 (now withdrawn), and is generally abbreviated to SWG. Use of SWG sizes has fallen greatly in popularity but is still used as a measure of thickness in guitar strings and some electrical wire. Cross-sectional area in square millimeters is now a more popular size measurement.