Ernesto Palla concert quality classical guitar strings are made of a solid nylon filament. Gold fourth, fifth, and sixth wound strings are made of 80/20 bronze plated copper wrapped around a nylon floss core providing a smooth, rich tone. All Ernie Ball strings are precision manufactured to the highest standards and most exacting specs to assure consistency, optimum performance, and long life. Gauges: First = .028, Second = .032, Third = .040, Fourth = .030, Fifth = .036, Sixth = .042 Medium tension.