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;D "Superior" ;String gauges/tension: ;Dolce 1.00mm/14.4kp/31.7lbs;Medium 1.01mm/14.7kp/32.3lbs;Forte 1.02mm/15.1kp/33.2lbs;