It's well known that Wawrinka was using (and probably still is) RPM Blast 16 but however in an interview with Tennis Head right around the time of his 2015 French Open victory (I don't know how to link it, but if you search Wawrinka strings on Google it will be one of the first things to come up) he says that he's been working on a prototype string with Yonex and during a period last year he could be seen playing with red strings which would seem to support this statement. Can anyone shed...
Wawrinka still using RPM Blast?
Wawrinka still using RPM Blast?