D‎'‎addario xl prosteels utilize a highly magnetic‎,‎ corrosion‎-resistant steel alloy that delivers super‎-bright tone without shrill overtones‎.‎ they offer a palette of harmonically rich‎,‎ brilliantly penetrating highs combined with pronounced‎,‎ tight‎-and‎-tough lows‎.‎ if you need a little more crunch‎,‎ bite‎,‎ and sustain‎,‎ prosteels are the string for you‎!‎From the ManufacturerEPS510‎'‎s offer a super‎-bright‎,‎ crunchy tone and corrosion resistance for longer string life‎.‎D‎'‎Addario XL ProSteels utilize a highly magnetic‎,‎ corrosion‎-resistant steel alloy that delivers super‎-bright tone without shrill overtones‎.‎ They offer a palette of harmonically rich‎,‎ brilliantly penetrating highs combined with pronounced‎,‎ tight‎-and‎-tough lows‎.‎ If you‎'‎re looking for more crunch‎,‎ bite‎,‎ and sustain‎,‎ ProSteels are the choice for you‎.‎D‎'‎Addario‎,‎ the world‎'‎s largest manufacturer of musical instrument strings‎,‎ is known as The Players Choice with a reputation for unsurpassed quality and consistency‎.‎ D‎'‎Addario‎'‎s innovative packaging reduces waste and provides protection from corrosion‎.‎ All D‎'‎Addario strings are manufactured in the U‎.‎S‎.‎A‎.‎ using proprietary‎,‎ digitally controlled‎,‎ state‎-of‎-the‎-art machinery for unmatched performance‎,‎ set after set‎.‎