Thomastik Infeld THPI-42 cello string D-2 4/4 medium, carbon steel, multialloy woundThomastik Infeld THPI 42 cello string D 2 4 4 medium, carbon steel, multialloy wound PETER INFELD strings for cello Centered tonal core Remarkable projection Exceptional sound colors that are easy to control Extremely reliable How our PETER INFELD cello strings make a difference so you sound your best Our PETER INFELD strings for cello make you shine in many different ways. The strings are very reliable and help you sound great with minimal effort.