Thomastik IF210 Electric Guitar Flatwound 12-String SetTHOMASTIK INFELD 12 ELECTRIC GUITAR FLAT WOUND FOR THE 60s SOUND: This flat wound set INFELD 12 NO. IF210 guitar strings is especially designed for Rickenbacker 12 string guitars. They offer a very balanced sound from string to string and from octave to octave. The tension measurement is based on a scale length of 25. 5" (648 mm). Technical Details NR. Note Material Gauge mm lbs kg DTP10 E plain steel, brass plated 0. 010 0. 26 17. 20 7. 80 DTP10 E