Now the standard among Phosophor Bronze strings, hex core acoustic strings have an added treble presence to the wound strings that make them the go to string for most acoustic guitar players. ThroBak Vintage Choice Phosphor Bronze strings are wound with the highest quality 92/8 Phosphor Bronze assuring the best possible tone and longevity. Enjoy the projection and playability of our hex core strings. Available with Tinned or Bronzed high E and B strings. Made in U.S.A. using only the finest U.S.A. wire.