Types of Tennis Strings, Explained

There are four types of tennis string. Polyester is a single stiff monofilament for control and durability; multifilament is hundreds of soft fibers bundled together for comfort and power; synthetic gut is a single nylon core with a wrap, the cheap sensible default; and natural gut is actual cow intestine, the best-playing and most expensive string there is. Almost every club player should be in one of the middle two.

String type matters more than most people expect — more than a racquet upgrade, for a fraction of the price. A frame you like, strung with the wrong material, feels like a frame you do not like. This page explains the four families and what each one is physically made of; the decision process, including gauge and tension, is at how to choose tennis strings.

1. Polyester (“poly”) — control and durability

What it is made of: a single extruded strand of polyester co-polymer, sometimes with additives — Luxilon's ALU Power adds a fluorocarbon resin and aluminum fibers. One strand, no bundle, no wrap. That is why it is called a monofilament.

What it does: it is stiff, so it deforms little on impact and returns little energy. That sounds like a drawback and is the entire point: a low-powered string lets a fast swing go at full commitment and still keep the ball in the court. Poly also holds its shape under shear, so the main strings slide sideways and snap back — which is the mechanism that actually produces topspin.

What it costs you: comfort and lifespan. Poly transmits more shock than any other family, and it goes dead— losing tension and elasticity — long before it breaks, typically in 10–20 playing hours. Playing on old poly is the single most common self-inflicted cause of tennis elbow in club tennis.

Who should use it: players who break strings inside a month, and 4.0+ players whose errors go long. Shaped and softened polys like Solinco's Hyper-G Soft split the difference and are the sensible first poly.

2. Multifilament — comfort and power

What it is made of: hundreds to thousands of microfibres — usually nylon, sometimes with polyurethane or Zyex blended in — bundled and bonded inside an outer coating. The construction deliberately imitates natural gut's bundle of collagen fibrils.

What it does: the bundle stretches and recovers, so the string bed deforms more, returns more energy and absorbs more shock. Depth comes easily, the feel is soft and the ball stays on the strings fractionally longer.

What it costs you: control at high swing speeds, and durability. A multifilament in the hands of a heavy hitter can break in a session, and when the outer coating abrades the inner fibers fray visibly.

Who should use it: anyone with arm trouble, anyone below about 4.0 who does not break strings, and anyone who wants natural gut's feel without natural gut's price. See strings for tennis elbow, where this family dominates the ranking.

3. Synthetic gut — the sensible default

What it is made of: a single solid nylon center core with one or more layers of smaller nylon filaments wrapped around it. Structurally it sits between a monofilament and a multifilament, which is exactly how it plays.

What it does: everything adequately and nothing exceptionally. Decent power, decent control, decent comfort, decent life, at a fraction of the price of either family above. It is the string most pre-strung racquets arrive with and the most-sold string in club tennis by a wide margin.

What it costs you: the top end of every characteristic. It does not control a 4.5 swing like poly and it does not cushion an injured elbow like a premium multifilament.

Who should use it: most 3.0–3.5 players, and anyone who would rather restring three times a year on cheap string than once a year on expensive string. That trade-off is correct more often than club players believe.

4. Natural gut — the best, and the most expensive

What it is made of: serosa, the outer membrane of cow intestine, cut into ribbons, cleaned, twisted into a cord and coated. It is a genuine animal product — one string set uses material from roughly three cows — and it is made essentially the way it was a century ago, which is why it costs what it costs.

What it does: the best power-to-comfort ratio of any string, and by a distance the best tension maintenance. A gut bed plays like a fresh bed for far longer than anything synthetic, which is part of what you are paying for.

What it costs you: money, and weather tolerance. Gut is damaged by moisture and should never be left in a damp bag. It also offers less spin potential than a shaped poly, because it grips the ball rather than sliding and snapping back.

Who should use it: players with persistent arm problems who have the budget, and advanced players in a hybrid — gut mains with poly crosses is the standard tour setup for exactly this reason.

Knowing the four families is the groundwork; picking one is the decision. How to choose tennis strings walks it through in three questions — do you break strings, does your arm hurt, and what do you want more of.

Two of these families account for most club string jobs, and they are easy to confuse because both are nylon. Multifilament vs synthetic gut puts them head to head on construction, comfort, tension maintenance, string life and real cost per restring, with a verdict on which club player should buy which.

Natural gut is the family on this page that raises a cost question rather than a performance one. It is the best-playing string made and the most expensive in tennis, and for most club players the honest answer is to buy a premium multifilament instead. Is natural gut worth it? sets out the three players it genuinely suits, the hybrid that halves the cost, and why moisture decides it for anyone who plays outdoors in the damp.