Originally known as Country Gold"s, Rotosound Super Bronze Guitar Strings are great sounding phosphor bronze acoustic strings due to their contact core design. Pioneered by Rotosound in 1974, Super Bronze are the choice for long sustain and brightness. These guitar strings also slightly reduce the action on any instrument and are available in 3, 6-string gauges: 6 String Sets: SB10: 10-14-20w-28w-40w-50w SB11: 11-15-22w-30w-42w-52w SB12: 12-16-24w-32w-44w-54w Please note: "w" denotes a wound string