Thomastik Infeld THRO-42 cello string D-2 4/4, carbon steel, multialloy woundThomastik Infeld THRO 42 cello string D 2 4 4, carbon steel, multialloy wound The Thomastik Infeld RONDO D string NO. RO42 is a present sounding string with an open, clear and radiant tone color. Despite this clarity, it has a profound keynote. The strings register is baritone, yet still brighter than other D strings in this spectrum. A special feature of the NO. RO42: Usually the G string on the cello is the supporting string for the entire set. But