D'Addario guitar strings are made from high-quality materials, such as bronze, phosphor bronze, and nickel-plated steel, to produce clear and bright tones. They offer a range of gauges to suit different playing styles, from light to heavy, and also offer different types of strings, including coated strings and flatwound 
XT strings are designed both for professional players who need to ready to play at any minute, demanding instant performance; and also players who just want to play and don't want the fuss of changing strings.