Thomastik-Infeld Versum Cello Strings VERSUM A and D inspire with their sweetness and their sunny and open sound, giving them height and air and a sense of warmth and fullness. VERSUM C and G enchant with a velvety warmth, a powerful round color, and beautiful depth. They create a smooth and saturated sound with a crisp texture that envelops your audience in its soundstage. Just like SPIROCORE, VERSUM is engineered around an ultra-flexible spiral core and the game-changing tungsten winding.