High-quality strings since 1956; Steel core, metal alloy or fiber winding; Warm, brilliant sound and durability; The “Classic” series standard strings; The A+D strings of the “Special” series are 0.01 mm thicker; The “Superior” strings are 0.02 mm thicker than “Special”; The “Silver Sound” G strings have a flexible steel core and silver winding; C “Classic” chrome steel; string thickness/-tension; soft 1.70mm/13.7kp/30.1lbs; medium 1.71mm/13.8kp/30.3lbs; forte 1.72mm/14.0kp/31.0lbs;