As a tennis racquet stringer, I get asked all the time what is the difference between Natural Gut tennis strings, and Synthetic Gut tennis strings.
Natural Gut strings is generally made from a cows gut in a complex process. Because of this, Natural Gut is the most expensive tennis string on the market. Natural Gut strings are popular among tennis professionals because of its superior performance. Natural Gut strings offer great elasticity, tension stability and liveliness. Because of the high price, Natural Gut may not be the best choice for recreational players. This is where Synthetic Gut strings come in.
Synthetic Gut strings come in a wide variety of materials, textures, colors etc.. Synthetic Gut strings are basically everything outside of the Natural Gut strings. Here is a breakdown of the different types of Synthetic Gut strings:
Nylon Strings are a good all-around string category. This is the basic, and most popular string choice in tennis. It also happens to be one of the cheapest. It has a crisper feel compared with Multifilaments, good, but not as gentle on the arm as Multi or Gut. It's reasonably durable and holds tension well. A good category of string when you're looking for power and control and affordability.
Examples: Gamma Synthetic Gut and Prince Tournament Nylon
Polyester & Kevlar
Polyester & Kevlar strings are known for their durability, and are a good choice for hard hitters, string breakers, and people without arm problems. Kevlar strings are extremely stiff, and are best used in a hybrid setup. Poly has much more playability, and its use is not limited to hybrid applications like Kevlar, and Poly holds tension fair. A good category of string when you're looking for maximum durability and control.
Examples: Kirchbaum Super Smashy Honey (polyester) and Ashaway Kevlar
Multifilament strings are the closest strings to Natural Gut, and are also the next most expensive strings. Best overall playability, and are gentle on the arm, but punishing to your opponent. Because they are made of hundreds of filaments, the fray as the wear. Holds tension fairly well. A good category of string when you're looking for a string that is arm friendly, powerful and has good control.
Examples: Wilson NXT and Babolat Fibertour
These are the strings that have an added raised band to give the string tecture. The idea of the this texture, is to grab the tennis ball and create more spin. Other strings such as Gamma Gut 2, have tiny groves that give the string more texture. Examples: Gamma Ruff and Prince Topspin Plus