An ultra-fine layer of EXP Coating is bonded to the phosphor bronze wrap wire which is then wound onto the hex-shaped core wire. The result is a built-in barrier against the corrosion and wear that can quickly sap the life out of your strings and your sound. EXP coated phosphor bronze strings have a natural round wound feel and sound fresh and bright with a "new string tone" that lasts three to four times longer than traditional guitar strings.
From the Manufacturer
EXP17s offer heavier tension resulting in a bolder, more resonant acoustic tone with higher resistance for heavy strumming and flat-picking.
D'Addario EXPs are the most natural-sounding, longest-lasting coated strings available. EXP Coated Technology starts with the highest quality wrap wire materials, precision drawn and micro-coated on our advanced proprietary machinery. Strings are then wound normally, delivering tone and feel identical to D'Addario's world renowned acoustic strings, with a minimum of 4 times more life. You won't believe they are coated!
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.