Coated with a special enamel for extra long life! Stringjoy, after much experimentation, have developed a balanced tension set of electric guitar strings that solves the big dips in tension on the 2nd (B string) and 6th (Low E string) found on the common light gauge string set. The result is a set of strings that intonates better and plays evenly across the entire fretboard. Made in Nashville, TN out of high quality materials with exacting standards.