Ernie Ball Slinky Acoustic Guitar Strings feature coated Titanium RPS Technology that resists rust and grime and brings you bright and powerful tone. Ernie Ball's titanium coated Slinky Acoustic strings are stronger and longer-lasting than traditional strings--either coated and uncoated strings. That's thanks in part to an exclusive protective coating on both the wrap wire and the plain strings as well as a patented winding of titanium wire around the lock twist of the ball end. Staying true to Ernie Ball's heritage of superb craftsmanship and sound quality, the 2156 Slinky Acoustic Guitar Strings are made with the finest and freshest raw materials, resulting in a crisp ringing sound with pleasing overtones. Gauges: 12, 16, 24, 32, 44, 54.