Either gut or carbon, by request. I used natural gut for all instrument from bass, for next 5 harps I’ll try to use carbon trebles.
Bernd Kuerschner calculates the tensions up to your request and/or measures. So, he works individually: the tension we have went out more balanced and delicate in range, meanwhile the Bow Brand we previously had is standart and didn’t fit on 100%. It takes slightly more time (about 2 weeks for big orders), but it worth. As a player, I must say that they are much more plesant to the fingers and have nicer respond to the touch.