Eagle Guitar Strings are manufactured from the finest materials sourced from the world's leading producers of core wire.  The wire is tested for best possible power production within the magnetic field of your guitar's pickup and for any irregularities that may cause dissonant overtones. Therefore giving a powerful full clear sound.  Made to American quality standards using the 'Annealing' process. This strengthens the wire making it less brittle and less likely to break, simultaneously removing all foreign substances, leaving the metal strong and flexible.