High Quality Standards : These strings are precision manufactured to the highest standards and most exacting specifications to ensure consistency, optimum performance, and long life. Anti-oxidation Coating : These strings feature a precision wound corrosion resistant phosphor bronze wire that is carefully drawn around a hexagonally shaped, high-carbon steel core. Color Metal String Head : Coated strings with expertly surface plated. Color protective film make more beautiful, rust-proof and sturdy. 10 Pack and Stored for 5 Years : Enough quantity , don't have to worry about a broken string affecting your performance. Precise technology and critical tension test make inside core and coating combine together reach to resonates homogeneous. The String's Wrap Wire Grips the Core to Create Superior Stability, Precise Intonation, Enhanced Durability.