D'Addario EJ17-B25 Phosphor Bronze Acoustic Guitar Strings, Medium, 13-56, 25 Bulk Sets D'Addario's most popular choice for heavy strumming, flat-picking and resonant, projecting tone in a convenient bulk pack of 25 sets Preferred for its warm, bright, and well balanced acoustic tone Bulk shop packaging is ideal for workbenches or anywhere bulk packaged strings are needed Made in the U.S.A. for the highest quality and performance String Gauges: Plain Steel .013, .017, Phosphor Bronze Wound .026, .035, .045, .056