GHS Strings GB7L 7-String Guitar Boomers, Nickel-Plated Electric Guitar Strings, Extra Light (.009-.058) Model: GB7L Featuring NitroPack singles, guaranteed fresh from the factory! 7-String Set featuring Roundwound Nickel-Plated Steel on a Hex Core Offers a brilliant tone and powerful attack, THE POWER STRING. Extra Light Gauge: 009-011-016-024-032-042-058