The D'Addario XSAPB1253 is a coated phosphor bronze acoustic guitar string set in a light gauge, .012-.053, a common all-around acoustic gauge balancing playability and tone. An ultra-thin XS film coats the wound strings and a polymer treatment protects the plain steels for longer life and a smooth feel. The set uses phosphor bronze wrap wire over an NY Steel core for warm, balanced acoustic tone and tuning stability. Made in the USA.