德國琴弦大廠 - Pirastro - 近年發佈的大提琴弦 Perpetual，擁有極高的可塑性及廣闊的音色頻譜：就如一所任由設計師發揮的寬闊別墅，甜美、溫暖、或是剛猛，無所不能。Perpetual 集中而清晰的音質，可將演奏家最細緻的演奏技法表露無遺。
Perpetual strings are characterized by great flexibility and an extraordinary tonal spectrum: from a sweet, warm tone to sheer endless power – everything is possible. The sound is like a large house with plenty of room for individual design. At the same time, the tone is focused and clear, the most delicate touches are instantly audible and the base warmth always present. The natural qualities and timbre of each cello are enhanced by the strings’ great dynamics and intensity.