NB1252BT Nickel Bronze Set, Balanced Tension Light, 12-52 D'Addario's premium uncoated acoustic string set that provides a crisp and clear sound to accentuate the unique tone of your guitar. Increased corrosion resistance for a longer lasting uncoated string Feature D'Addario's exclusive high-carbon NY steel for unprecedented strength and tuning stability Made in the U.S.A. for the highest quality and performance String Gauges: Plain Steel. 012. 016, Nickel Bronze Wound. 022. 030. 039. 052.