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 D'Addario's proprietary XT coating, a significantly extended lifespan. Coupled with Carbon trebles, which are the brightest, best projecting trebles D'Addario have to offer, XT Dynacore is the most advanced classical string available. This Hard tension set provides rich tone and strong projection.  025, 028, 034, 029w, 036w, 046.