I'm currently playing a 915D2. I previously played the 910D2. I played the YS6 in the 910 but was fitted by a professional fitter and was told the rouge black was a better fit. While performance / distance was improve consistency wasn't. I recently put the YS6 on the 915. What a positive difference. I'm back to driving it high and long for me. I see that Graphite Design now makes the YS6 Nano. What I've read is positi e. Please share if you have experience with both shafts and can offer a comparison.