Famous for first-class strings since 1956;Steel core string wound with thin filaments of pure or alloyed metal;Warm, brilliant tone and long life;"Classic" Series - standard strings;"Special" Series has 0.01 mm thicker A+D strings;"Superior" Series is 0.02 mm thicker than "Special";"Silver Sound" Series has G and C strings made of a highly flexible steel core with a top coil of pure silver;A "Superior";String gauges/tensions: ;dolce 0.77mm/17.7kp/38.9lbs;medium 0.78mm/18.5kp/40.7lbs;forte 0.79mm/19.1kp/42.0lbs;