XT are longest lasting classical strings, combining centuries of D’Addario expertise with modern coating technology. The Dynacore bass strings in this XT set use a revolutionary multi-filament nylon core processing technique to deliver unparalleled intonation, responsive attack, and crystal-clear projection—and with addition of proprietary XT coating, a significantly extended lifespan. Coupled with precision Titanium trebles, supplying distinct balance and increased resonance, XT Dynacore is the most advanced classical string available.