Ernie Ball Twelve String Acoustic Guitar - Earthwood 12 String Light, .009 - .046, 2010

Plain String

"Plain strings sound the higher pitch notes. Plain string is unwound. Made of specially tempered tin plated high carbon steel, but its shape is round, not hex. Used on electric and acoustic guitars, banjos, mandolins -- not classic guitars. One end has a brass grommet, called a ball, which is secured by a special lock twist. The ball is for attaching the string to an instrument.

Acoustic Guitar - Earthwood Bronze

Wound strings are wrapped with an alloy of 80% copper and 20% zinc wire. The most popular acoustic string, providing a crisp, ringing sound, with pleasing overtones.

Core Wire

Core wire is the center of a wound string. It is of specially tempered high carbon steel. The crosscut end view reveals a shape that is not round, but hex shaped. The points of the hex shape help hold the wrap wire securely in place. Hex core wire is used for the wound strings of both electric and acoustic guitars, banjos, and mandolins - but not classic guitars."