Approved by bluegrass studio musicians for high-frequency clarity with the light strings, and low-frequency thump for the lower strings.This bluegrass set also features a unique treatment called EMP that coats the entire string with an ultrathin protective film. Its the thinnest coating ever applied to guitar strings less than one micron and will withstand more abuse from hard strumming than coatings 1000 times thicker EMP ensures longer string life by protecting strings from corrosion due to skin acidity, salt, and moisture without compromising feel and sound. • MFSKU 7423 • UPC 786136074237