Curt Mangan Fusion Matched strings 12 – 56 80/20 Bronze Bluegrass gauges 12/16/24 W/: 36 – 46 – 56 (bluegrass) Length of string length 43 inches (109 cm) 80/20 Bronze strings are of old-school, vintage or bright bronze. To the early 1970s, 80/20 Bronze was the preferred material around to produce these strings for acoustic guitars. 80/20 Bronze is made from 80% copper and 20% zinc. They offer balanced treble and bass, with a slight emphasis the centre area to make the tone Durchsetzungsfähiger.