Gibson SAG-MB10 Acoustic Guitar StringsGibson Acoustic Guitar Strings Gibson strings have been made in the USA since 1907! They use only premium us materials and vacuum pack each package for freshness. Gibson strings are standard equipment on all Gibson guitars and feature proprietary cover to core ratios for great feel and tone, utilize the hex core of Swedish steel for crisp response and sustain, and are slow wound using Gibsons proprietary tension release system for optimum tone. There