D'Addario EJ-15 Phosphor Bronze 10-47D'Addario pioneered Phosphor Bronze strings in 1974, now globally standard, offering versatile, warm, and balanced tone on 10 47 Extra Light strings suitable for all styles. Precision wound with phosphor bronze over a steel core. Deliver warm, balanced, and versatile acoustic tone. Industry standard since the 1970s, pioneered by DAddario. Comes with a registration code for rewards via the recyclable VCI bag. Made in the USA at DAddarios New York