The Thomastik-Infeld Spirit! cello string is based on a steel core with chrome winding. For smaller sizes (1/4 -1/2) a tungsten winding is used for the C string. According to the manufacturer, the strings have an easy response; they feel nice and they last a long time. In addition, we have a warm sound. There are many choices in this price segment and trial and error is actually the best way to determine which string best suits the individual cello.
Thomastik has terminated the fabrication of small sizes. Some sets/strings are still available.
Click here for the datasheet of Thomastik Spirit cello strings.