BlackSmith acoustic guitar strings are made with the finest materials and manufactured using state-of-the-art automatic servo controlled winding equipment. USA made 80/20 Bronze and steel ensures a long lasting string with increased sustain and purer tone. Our proprietary computer controlled winding technology produces strings with a very consistent wrap surface and even tension, resulting in stable tuning, accurate intonation, and superior playability. The Micro Carbon Shield coating, AAOT, prevents oxidation and dirt build-up on the wound strings and are designed to last even longer than our flagship, AOT (Anti-Oxidation Technology) strings. Sub-Zero Treated plain steel strings offer brilliant tone with a silky feel. With BlackSmith Micro Carbon shield coated acoustic guitar strings, you will experience the perfect balance of consistency, tone, durability, and performance.