Its surface is somewhere between roundwound and flatwound. It's smooth, but you can feel the rolling on it a little. The thinner part above the keys is wrapped in green textile, this part is also suitable for fairly long keys arranged in a single row. At the other end of the string, the balls were colored. Its quality is very good, it started quickly after installation and keeps the tuning. His voice is full and balanced. I am satisfied, I would buy/purchase this again.