GHS Strings BB10U Bright Bronze, 80/20 Copper-Zinc Alloy, Acoustic Guitar Strings, Ultra Light (.010-.046) Model: BB10U Featuring the air-tight Fresh Pack & NitroPack singles, guaranteed fresh from the factory! 80/20 Copper Zinc alloy on a Hex Core Unique core-to-cover ratio. Ultra Light Gauge: 010-013.5-020-026-036-046