Rondo String Upgrade VAThomastik Infeld's Luthier Series line features Rondo viola strings! These strings were specially designed for the sophisticated violist and to meet the professional needs of luthiers. The Rondo String set from Thomastik Infeld fits viola sizes 15"16. 5" and is medium weight. Rondo strings are powerful with a quick bow response, but offer a strong and complex tone usually not found on strings this powerful. They are a top choice for discerning