HEAD Tennis Strings Explained: Hawk vs Lynx vs Sonic Pro vs Velocity — Which One Is Right for You?

HEAD makes some of the most widely played strings on tour and in club tennis, but the range spans a lot of ground — from one of the stiffest co-polys available to a soft multifilament that suits beginners and arm-sensitive players. The problem is that the names give very little away. Hawk, Lynx, Sonic Pro, Velocity — none of that tells you whether a string is stiff or soft, round or shaped, or whether it belongs in the mains of a heavy hitter or the frame of someone who needs to protect their elbow.

This guide cuts through that. It covers every HEAD string the store carries, explains what each one is and who it suits, and tells you which family to start with based on how you play.

The HEAD String Range at a Glance

HEAD Hawk — The Stiff Tour Co-Poly

HEAD Hawk is the string that made HEAD a serious presence in the co-poly market. It is stiff — around 1.05 kg/mm on USRSA static stiffness tests — which puts it in the same tier as Luxilon Alu Power and Solinco Hyper-G. That stiffness is the point. It gives Hawk exceptional control and excellent tension retention, meaning the string holds its characteristics well over time rather than going dead quickly the way cheaper polys do.

HEAD built Hawk around their Crystal Core construction — a proprietary method that influences how energy transfers at contact. The result is a string that feels distinctly lively off the stringbed for a co-poly, with more feedback and pop than you typically get from a stiff monofilament. It is round-profiled, which means it slides and snaps back moderately well rather than generating aggressive bite like a shaped string would.

Hawk suits players who already have strong swing speed and technique, are looking for control and consistency over raw power, and don't have arm issues. It is not the right starting point for juniors, beginners, or anyone with a history of tennis elbow.

Hawk Touch — The Tour Player's Hawk

Hawk Touch uses a fundamentally different construction from standard Hawk. Rather than a single-material monofilament, it is co-extruded — a firm outer polymer shell wrapped around a soft, elastic inner core. That inner core absorbs shock and creates a more pocketed, settled feel at contact, while the outer shell maintains the control and durability characteristics the Hawk family is known for.

The stiffness numbers are worth noting: Racketpedia lab data puts Hawk Touch at roughly the same static stiffness as standard Hawk (~1.05–1.15 kg/mm depending on colour variant), which runs counter to what most players expect. The reason it plays softer is the elastic core — it changes how energy transfers through the string at contact, dampening vibration and creating a more cushioned feel, even though the raw stiffness measurement is similar. So Hawk Touch is not easier on the arm in the way a genuinely lower-stiffness string like Lynx or Sonic Pro is — the comfort gain comes from the construction character, not a lower force profile.

This is the string Alexander Zverev and Jannik Sinner have both used, which tells you where it sits: it's a tour-grade co-poly that delivers feel and control in equal measure. Players who want the Hawk experience but find standard Hawk too harsh — or who are chasing better feedback on touch shots — will find Hawk Touch a meaningfully better fit.

Hawk Touch Rough — Spin Added to the Touch Formula

Hawk Touch Rough takes the identical co-extrusion construction of Hawk Touch and adds a textured, roughened outer surface. That surface creates additional friction on ball contact — more grip, more bite, more topspin and slice potential — without changing the core feel of the string. It plays slightly softer than Hawk Touch (the textured surface reduces the crispness of ball contact marginally) and is the most comfortable variant in the Hawk family.

The spin gain over standard Hawk Touch is real but measured — it is not as dramatic as switching to a shaped poly like Lynx Tour, because the profile is still round. Think of it as: if you already like Hawk Touch but want a bit more spin without changing anything else, Touch Rough gives you that. If you are starting from scratch and spin is the primary goal, Lynx Tour is a more direct route.

Note: Hawk Touch Rough is a HEAD product but is not currently listed in this store's range. Hawk Touch is stocked and is the natural starting point for most players considering this family.

Full breakdown of all Hawk variants: Head Hawk Strings Explained — Hawk vs Touch vs Power vs Tour rPET

HEAD Lynx — The Accessible Co-Poly

HEAD Lynx is HEAD's answer to the question of what a co-poly feels like when it's actually comfortable. At around 0.68 kg/mm static stiffness, it sits well below Hawk and comfortably in the range of softer polys like Babolat RPM Blast or Tecnifibre Black Code. That softer construction makes it more forgiving on the arm than Hawk, and it generates a quicker snapback effect at contact — which contributes to easy spin without needing elite technique to activate it.

Lynx is round-profiled and plays with a smooth, settled feel that suits club-level players and intermediates who want a proper co-poly without the harshness that stiff polys can deliver. It doesn't have Hawk's level of control, but it is more accessible and easier on the body, making it a better fit for players who play 3–4 times a week and want a string that performs consistently without punishing missed technique.

Lynx Tour takes the Lynx formula and adds a hexagonal profile — six edges that dig into the ball and generate more aggressive spin and bite. The result is meaningfully different from standard Lynx: more spin potential, more control on high-speed shots, and a slightly firmer feel at contact. Thiem used a version of Lynx Tour in his Indian Wells setup, which gives you a sense of where it sits on the performance spectrum. If you're choosing between Lynx and Lynx Tour, the standard Lynx is more comfortable and all-round; Lynx Tour is for players who specifically want more spin and bite from their HEAD string.

Full breakdown: Head Lynx Strings Explained — Lynx vs Lynx Tour vs Lynx Edge vs Lynx Touch | Lynx Tour in-depth review

HEAD Sonic Pro — The Softest Co-Poly in the Range

HEAD Sonic Pro is where HEAD's co-poly range gets genuinely arm-friendly. It tests around 0.63 kg/mm static stiffness — the softest co-poly in the HEAD lineup and soft enough to sit in the same conversation as strings like Tecnifibre TGV or Volkl V-Torque Tour. That softness means it generates more power and comfort than Lynx or Hawk, at the cost of some control and tension retention.

Sonic Pro suits players who want to stay in the co-poly world for the durability and tension stability benefits but can't tolerate stiffer strings on their arm. It is also a reasonable choice for hybrid setups — Sonic Pro in the crosses paired with a stiffer shaped poly in the mains is a combination that delivers good spin from the mains while the Sonic Pro cross softens the overall feel of the stringbed considerably.

The trade-off versus Lynx is worth naming plainly: Sonic Pro is easier on the arm and more powerful, but it goes dead faster and gives you less of the controlled, precise response that poly players are typically after. If arm comfort is your primary concern but you still want to play poly, Sonic Pro is HEAD's best answer. If you want the most arm-friendly HEAD option overall, that's the Velocity MLT below.

HEAD Velocity MLT — The Multifilament for Arm-Sensitive Players

HEAD Velocity MLT is a different category entirely. It is not a co-poly — it is a multifilament, made from hundreds of micro-fibres twisted together in a construction that mimics natural gut's feel more closely than any monofilament can. That construction makes it significantly more elastic than any of the polys above, which translates to more power, more comfort, and considerably more arm protection.

The static stiffness figure of around 0.73 kg/mm sounds similar to Lynx, but the comparison is misleading — multifilament stiffness behaves differently from mono stiffness at contact. In practice, Velocity MLT feels noticeably softer and more cushioned than any co-poly at the same stiffness rating. Players recovering from tennis elbow, beginners who haven't built up arm conditioning yet, and recreational players who want a comfortable ride without thinking about string science will all find Velocity MLT a strong choice.

The downsides relative to co-polys: it breaks faster (especially for heavy hitters), it loses tension more quickly, and it doesn't give the same level of spin or control. But for the player it's designed for, those trade-offs are entirely acceptable.

HEAD RIP Control — The Nylon Entry Point

HEAD RIP Control is a synthetic gut — nylon-based, durable, and designed to be a no-fuss all-rounder at a budget price point. It doesn't offer the feel of a multifilament or the control of a co-poly, but it is forgiving, holds tension reasonably well for a nylon string, and is the right choice for beginners who are still developing their game and don't want to spend more on strings than they need to.

Once a player starts hitting consistently and looking for more from their strings, RIP Control is the natural string to move on from — towards Velocity MLT if arm comfort is the priority, or Lynx if they're ready to try a co-poly.

HEAD Intellitour — The Hybrid Option

HEAD also offers Intellitour hybrid sets, which pair a co-poly main with a multifilament cross. This is HEAD's pre-packaged answer to the hybrid setup question — the co-poly mains give control and spin, while the multifilament crosses soften the overall stringbed feel and protect the arm. It's a convenient option for players who know they want a hybrid but don't want to select the component strings individually.

Which HEAD String Should You Choose?

If you're a competitive player with full swing speed and no arm issues: Start with Hawk. It's the most controlled, most tour-appropriate string HEAD makes. If you want more spin bite, consider Lynx Tour instead.

If you want Hawk's control profile but with better feel and arm comfort: Hawk Touch. The co-extrusion construction gives it a softer, more pocketed response — it's what Sinner and Zverev use, and a worthwhile step down from standard Hawk without giving up control.

If you want Hawk Touch's feel plus more spin: Hawk Touch Rough. It adds a textured surface to the Touch formula, giving a modest spin boost at a marginally softer feel. Note it's not currently stocked in this store — Hawk Touch is the closest available option.

If you're an intermediate player who wants a co-poly that isn't harsh: Lynx is your entry point. It's accessible, comfortable by co-poly standards, and gives you the spin and control benefits of a monofilament without the arm demands of Hawk.

If you want spin and control specifically: Lynx Tour over standard Lynx. The shaped profile makes a meaningful difference in how aggressively the string bites and releases.

If you play poly but have had arm issues: Sonic Pro is HEAD's softest co-poly, or consider a Sonic Pro cross in a hybrid with a shaped poly main. That combination gives you spin from the mains and comfort from the crosses.

If you're a beginner, recreational player, or have significant arm sensitivity: Velocity MLT. It's the most comfortable string in the range and the most forgiving on the arm.

If you're just starting out and want the most affordable option: RIP Control. It does the job at a price that makes sense while you're still figuring out what you want from a string.

Frequently Asked Questions — HEAD Strings