Quality strings since 1956; Steel core, metal alloy or fibre 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; G “Classic” chrome steel; string thickness/tension:; soft 1.16mm/13.0kp/28.6lbs; medium 1.17mm/13.4kp/29.5lbs; forte 1.18mm/13.6kp/29.9lbs;