Count the string loops at the bottom bridge of your racket — the curved section where the handle meets the head. If you see 3 loops, choose the 3-cylinder Retenser. If you see 4, choose the 2-cylinder version. Not sure? Send us a photo of your bridge to info@retenser.com and we'll confirm immediately.

The Standard comes with one cylinder set (medium tension). The Pro comes with three — soft, medium, and hard — letting you choose exactly how much tension you restore. The Pro also includes two adjustment keys and a storage pouch. If you play competitively, on multiple surfaces, or you're particular about your equipment, the Pro is built for you.

Soft (blue): adds 0.5 kg per click, 1 kg total — fine-tuning. Medium (white): adds 1 kg per click, 2 kg total — everyday restoration. Hard (orange): adds 1.5 kg per click, 3 kg total — maximum restoration after significant tension loss.

Yes. The installation process is straightforward for any experienced stringer. Each box includes a QR code linking to the installation video — a few minutes of watching is all they need. If your stringer has questions, they can contact us directly at info@retenser.com.

The Retenser fits almost every modern tennis racket. Each unit ships with two base parts — one slightly flat, one slightly rounded — to match different bridge profiles. Both are made from flexible material that adapts to your racket's shape.

Always start in the minus (Start) position. This gives you two full adjustments in reserve — Start to Middle, then Middle to Plus. All cylinders must be set to the same position for even tension across the string bed.

The Retenser adds approximately 5 grams — less than 2% of racket weight. It also replaces the existing grommet strip at the bridge, which partially offsets this. The Retenser sits exactly at the racket's geometric centre, so balance disruption is minimal.

Indefinitely, with normal use. The Retenser is built from high-strength materials designed to withstand repeated string tension forces. It can be reinstalled with every restring for years. When it's time for a new one, you'll know — the cylinders will stop clicking cleanly into position.

Yes. The Retenser is officially approved by the International Tennis Federation (ITF) and is legal for use in all professional and amateur competitions worldwide. You can download our ITF approval letter directly from the footer.

When strings crack, fray, or no longer spring back into alignment after shots, it's time for a new set. The Retenser extends the useful tension life of your strings significantly — but it doesn't change the physical condition of the string material itself.

Restringing costs €20–50 each time and requires booking a stringer, waiting, and collecting. Across a season, that adds up fast. The Retenser lets you maintain peak string tension on your own schedule, at no additional cost, between restrings. Most players using the Retenser find they can go significantly longer between restring appointments — saving time and money across the entire season.

Yes — and this is one of its most surprising benefits. Because the strings are routed through the Retenser rather than through the standard bridge grommet, the effective string length is slightly extended. This immediately enlarges the sweet spot, giving you more powerful and forgiving shots from the very first use.