String Materials & Construction

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What a string is made of, and how it's built, decides most of how it plays. Here is how the families compare, what each is actually made from, and which Golden Set string belongs where.

  • Material sets the baseline — stiffness, power, spin potential and how long the string lasts.
  • Construction (solid core, multifilament, shaped or smooth) fine-tunes feel, bite and durability.
  • Gauge and tension dial in the rest. Those have their own pages: gauges and tension.

At a glance

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String type Feel Spin Durability Holds tension Best for Golden Set
Co-polyester Firm, controlled Highest Highest Fair — restring on a schedule Players who swing fast and want control and spin; frequent string breakers Snake-Bite, Hex Poly, Smooth, Power Cord
Solid core Medium, crisp Medium Good Good All-round value; the classic cross string in a hybrid Synthetic Gut
Multifilament Soft, powerful Medium Lower Good Comfort and arm-friendliness; closest feel to natural gut Satin, Velvet
Natural gut Softest, liveliest Medium Lower (weather-sensitive) Best The reference point for feel; expensive —
Aramid (Kevlar) Very stiff Low Extreme Fair Chronic string breakers; largely replaced by co-polyester —

Co-polyester

Golden Set Material
A polyester blended with other polymers — hence "co-poly". The pure polyester of the early days was harsh and dumped tension fast; modern co-polyesters are softer, hold tension better, and are now the most-used string type on tour and among serious club players.
Construction
A single extruded filament. Round profiles are smoothest; shaped profiles — hexagonal like Hex Poly, or the twisted seven-sided Snake-Bite — add edges that grip the ball for extra spin.

What that means on court

Co-polys are firm and relatively low-powered, which is exactly why they work. There is less trampoline off the string bed, so you can swing hard and still keep the ball in. The slick, stiff strings slide sideways on impact and snap back, and that snap-back is where the extra spin comes from. Durability is excellent — they resist notching far better than softer strings.

The trade-off is feel and tension life. A co-poly feels stiffer at the same tension, and it sheds tension steadily as you play, going "dead" — low, erratic launch — well before it ever breaks.

Restring on a schedule, not on breakage. Most players want a fresh co-poly every 15–25 hours of play. If it feels stiff, drop a few pounds next time rather than switching string.

Want the spin without the harshness? Run the co-poly in the mains only and something softer in the crosses. Hybrid guide →

Hex Poly co-polyester monofilament construction, hexagonal cross-section
Hex Poly: a single co-polyester filament with a hexagonal profile.

Solid core

Golden Set Construction
A single solid core for elasticity, wrapped in one or more outer layers for abrasion and notch resistance. The core polymer is more elastic than polyester, which is where the extra power and livelier feel come from.

This is the workhorse of tennis strings, and the best value in the sport. Good performance, good durability, easy on the arm, easy to string, and inexpensive enough that stringing often stops being a financial decision.

It is also the most common way to soften a polyester setup — a solid core in the crosses takes a meaningful amount of the sting out of a poly bed while costing very little. Golden Set Synthetic Gut stands up against the industry-leading names at a fraction of their price.

Multifilament

Golden Set Construction
Hundreds of fine fibres twisted and bonded together instead of a single core, usually under a thin protective jacket. That bundled structure is what gets closest to natural gut.

Softer, more powerful and noticeably easier on the arm. The many-fibre core absorbs shock the way natural gut does, at a small fraction of the price — which is why it is the first thing to reach for if your elbow is complaining.

The price of that softness is durability. Fibres fray as the string wears, and multifilaments notch faster than a solid core or a co-poly. Velvet is the plush, forgiving one; Satin adds a low-friction coating for better snap-back and longer life, which also makes it the better choice as a cross string in a polyester hybrid.

Golden Set Velvet multifilament construction: bundled fibre core inside a jacket
Velvet: a multifilament core inside a protective jacket.

Two you'll hear about but rarely need

Natural gut

Made from twisted strands of cow intestine, natural gut is still the softest and most elastic string there is, and it holds tension better than anything else. It is also by far the most expensive and it dislikes moisture. Most players get the large majority of that feel from a good multifilament, and the pros who use gut usually pair it with a co-poly in a hybrid rather than stringing a full bed.

Aramid (Kevlar)

Extremely stiff and very nearly unbreakable. It was the answer for chronic string breakers before modern co-polyesters arrived. Today a shaped co-poly gives comparable durability with far better feel, so aramid has mostly disappeared from the game. We don't make one.

Choosing

  • Spin and control, and you swing with pace? Co-polyester — Snake-Bite for maximum bite, Power Cord for the softest poly feel.
  • Comfort, power, or a sore arm? A multifilament (Velvet, Satin), or a co-poly/multi hybrid.
  • Best all-round value, or a cross string for a hybrid? Synthetic Gut.
Shop all tennis strings → Compare cost per restring →

Related: Hybrid guide · Tension explained · Gauges explained

Golden Set strings are made in the same factories as the major brands and sold direct in bulk reels. A 660 ft reel restrings roughly 16 racquets. Updated September 2026.