The D'Addario XSAPB1152 is a coated phosphor bronze acoustic guitar string set in a custom-light gauge, .011-.052, offering slightly more volume and projection than extra-light while remaining easy to play. An ultra-thin XS film coats the wound strings and a polymer treatment protects the plain steels for extended life and a smooth feel. The set uses phosphor bronze wrap wire over an NY Steel core for warm, balanced tone. Made in the USA.