Cleartone Sevilla Classical Strings Ball End Medium Tension At long last, coated classicals 28-32-40-30-36-42 Sevilla Classical Guitar Strings feature the patented Cleartone EMP Coating (Enhanced Molecular Protection) With its one micron coating, the Sevilla Strings treatment is the thinnest in the industry, designed to last a long time without compromising the feel and sound of traditional strings "Silver wrapped wound strings are very susceptible to tarnishing," says product manager Jose Antonio "With our EMP Treatment, Sevilla Strings last a long time while maintaining the natural feel and sound of traditional strings