Multi-fiber tennis string is a bundle of extremely fine synthetic fibers twisted together to form a string, and its structure is similar to natural gut string. The multi-strand structure of nylon is superior to the structure with inner core in terms of comfort of shock absorption when hitting the ball, and the ball feeling is similar to natural gut string. At the same time, because this kind of string is soft and comfortable when hitting, it is more suitable for players who have tennis elbow but can't afford natural gut string. However, like the natural gut string, this kind of string will cause damage to it when hitting the ball, and may also cause the tennis line to bifurcate, so its service life is between the natural gut string and the cored composite string.

Polyester string polyester is another durable ball string material, which is wrapped with a layer of polyethylene material outside many nylon strings to make them integrated. Nowadays, more and more professional players have used the strings made of this material. However, the polyethylene material itself loses its elasticity faster than other artificial strings, so it is often used by leisure players mixed with Kevela strings.