The Brilliant advanced synthetic core set is intended for players who seek the most projecting sound. It also offers quick tuning stability. Synthetic core strings need about three to four days to settle in before achieving full tone quality. 

(Hydronalium D - Ball End E)

Two D strings are available. D - hydronalium which provides a projecting sound with plenty of attack when needed. D - silver which provides a warmer and mellower sound.