It is made of a single polyester or co-polyester thread. This stringing is very stiff. In addition, it can take a different shape (round, octagonal, hexagonal, pyramidal, etc.) to increase spin.
• Very high level players breaking often. (less than 10 hours of play);
• Powerful players playing with spin;
• Not recommended for children (age 13 and under, even competitive players);
• Intensive players playing 3 or more times a week.
More info: tennis elbow is a very common injury caused by a wrong choice of stringing and bad tension. Very often, high-level players still use mono-filament rather than hybrid or multi-filament stringing.