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Yes—the Sinn Dual Strap System was a real accessory. Introduced around 2016, it combined a compatible Sinn mechanical watch and an Apple Watch on one wrist using shortened strap sections, Apple Watch connectors and a bridge arrangement. Contemporary documentation specified Sinn watches with 22 mm lugs and Apple Watch models in the 38 mm and 42 mm size families. The reported price was €175, or €100 extra when ordered with a new Sinn watch. The original system now appears to be a historical product rather than a clearly current Sinn accessory.
Do not confuse it with Sinn’s current DuoFlex diving strap, which is a different product and does not mount an Apple Watch.
What the Dual Strap System did
This was not simply two ordinary bands worn side by side. It was a purpose-built combined strap:
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- Shortened strap halves for the Sinn watch.
- Shortened strap halves with Apple Watch-compatible connectors.
- A bridge or joining section that held both watches in one wrist-worn arrangement.
- Replacement spring bars, a strap-changing tool and a storage case, according to contemporary reports.
The French publication WatchGeneration described it as two small straps attached together, with one mechanical watch and one Apple Watch mounted to the resulting band.
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- Anti-Fade Plating – Crafted from high-grade material with advanced plating technology, these watch lugs resist fading while ensuring outstanding durability. The sleek finish enhances your smartwatch with both longevity and style, making it an excellent connection replacement and ideal for damaged bands or for use with normal insert conversion kit attachment pieces.
- Easy Damaged Lug Replacement – Refresh your watch by replacing worn or damaged lugs with this quality clock spring bars compatible design. Effortlessly switch to your favorite watch band for a new look or special occasion without hassle.
- Long-Lasting Construction & Robust– Featuring premium metal and strong connecting rods, these lugs provide a secure, reliable connection for your watch band, reducing the risk of accidental detachment during daily wear.
- Precise Replacement for 18–22mm Smartwatches – Engineered for smartwatches with 18–22mm connectors, ensuring a seamless fit and broad compatibility with popular models.
- Effortless Strap Swapping with Included Spring Bars – Two 18–22mm metal spring bars are included, making strap changes quick and tool-free so you can easily match your watch to your personal style. This connection replacement option ensures long-lasting performance while keeping your accessories compatible and stylish.
Why wear both watches?
The Sinn supplies mechanical-watch character, conventional timekeeping and the look many enthusiasts prefer. The Apple Watch adds notifications, calls, timers, activity tracking, health features and apps. The system was intended for people who did not want to choose between those roles—potentially collectors, pilots, engineers or anyone who uses the Apple Watch mainly as a utility device.
It was always a niche idea. Contemporary reaction included criticism that two cases looked bulky or awkward; an online poll cited by MacTechNews is anecdotal, not representative market research.
Compatibility: the limits that matter
| Component | Documented compatibility |
|---|---|
| Sinn watch | Models using 22 mm lug width |
| Apple Watch | 38 mm and 42 mm case-size families |
| Later Apple Watch sizes | Not automatically compatible; confirm with the seller |
| Sinn DuoFlex | Separate diving strap system for selected U-series watches |
The 2016 specification should not be extended to later Apple Watch families such as 40, 41, 45 or 49 mm without confirmation. Apple Watch connector families and conventional watch lug widths are different measurements. A 20 mm Sinn, an integrated-lug case or an unusual case design is not automatically suitable.
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- 【Durable Metal Construction】These 18mm to 20mm watch band adapter are made of high-quality alloy steel, offering exceptional durability and fade resistance. The smooth finish complements any smartwatch, ensuring a stylish and long-lasting connection.
- 【Easy Strap Replacement】These watch band adapter are designed for easy strap replacement, featuring quick-release pins for tool-free strap changes. Perfect for those who frequently update their style or replace damaged lugs.
- 【Secure Fit for 18-20mm Straps】These watch band adapter are designed specifically for smartwatches with 18-20mm connectors, providing a secure and seamless connection. The precise design ensures compatibility with a wide range of popular smartwatch models.
- 【Reliable Connection】These watch band adapter come with an original connecting rod, ensuring a stable and reliable connection for your watch band. The robust construction minimizes the risk of accidental detachment, giving you peace of mind during daily wear.
- 【Versatile and Practical】These universal metal watch band adapters are a versatile accessory, ideal for replacing damaged lugs or wanting to switch to a strap you prefer. The included spring rod makes strap replacement quick and hassle-free, enhancing your smartwatch experience.
How the arrangement works in daily use
The Sinn is generally worn on the outside of the wrist and the Apple Watch on the inside, where its rear sensors can contact skin. That positioning is a practical recommendation, not proof of medical-grade or workout accuracy. The original reports did not provide laboratory testing of heart-rate, sleep, fall-detection or exercise performance.
Before relying on the Apple Watch, check that:
- The sensors remain flat against skin and the band is neither loose nor painfully tight.
- The Digital Crown and side button are reachable in the chosen orientation.
- The arrangement does not block charging or require awkward removal.
- The combined cases do not press into each other, your wrist or clothing.
Two watches add mass and thickness. Large Sinn divers or chronographs can consume much of a small wrist, catch on cuffs and gloves, or create pressure at the case backs and lugs. A tighter fit may help sensor contact while making the mechanical watch uncomfortable. These are design trade-offs; comfort depends on wrist size, case thickness, strap material and placement.
Can the watches be worn separately?
Yes, contemporary coverage says the kit included a separate bridge strap so the watches could be used individually. When buying used, confirm that the bridge strap is actually included; sellers may offer only part of the original kit.
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- Broad Model Compatibility: Fits popular 16mm lug digital sport watches. Precision-engineered for dw6900, dw-9052, gwm5610, gw-m5610, gw6900, and gd 110. Also perfectly fits classic square series like the 5600, dw5600, and the smart dw-h5600. Easily upgrade your watch interface to fit any premium 22mm lugs straps.
- Versatile Strap Customization: Switch styles instantly. This watch band adapter allows you to trade your stock resin strap for a rugged paracord watch band, a tactical NATO strap, or a sleek metal band. It works as the ultimate strap replacement solution, giving your favorite timepiece a premium metal watches look.
- Complete All-in-One Kit: Everything you need for an easy DIY upgrade. This full package includes 4 pack connectors, 12 pieces durable spring bars, and 2 pieces installation tools. It provides a total solution for multiple watch pins replacement and adjustments, serving as the perfect watch replacement parts bundle.
- Durable & Rock-Solid Fit: Made from heavy-duty, high-impact ABS material. These replacement parts offer a tight, secure fit with zero rattling. Built for daily sports, tactical use, or heavy outdoor activities, it ensures a reliable link between your watch case and your new watch bracelet or 16 mm watch strap.
- Cost-Effective Maintenance: A smart alternative to high-priced original factory pieces. If your watch connector or anillo (band keeper) is broken, this budget-friendly replacement band kit allows you to refresh your classic dw-6900 or 5610 without buying an expensive whole new timepiece.
Price and availability today
MacTechNews reported €175 as the standalone price and a €100 surcharge when the system was ordered with a new Sinn watch. Those are historical 2016 prices, not current retail quotations.
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The original Apple Watch system is therefore best treated as historical or old stock unless Sinn or an authorized dealer confirms availability. A reseller reference, such as an older Sinn 836 listing, does not prove that Sinn still manufactures it.
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- Compatibility: Fit for GA-110/100/120/150/200/300/400, GD-100/110/120/G-8900/DW-5600, GW-M5610/DW-6900/G-5600, GW-6900/DW-9052/GLS-8900.
- 16mm to 22mm: The size of the protrusion is 16mm. Easily convert a 16mm port to a 22mm band, making your watch compatible with a wider variety of stylish 22mm straps.
- Package includes: 4 black adapters + 12 spring ears + 2 tools. Note: Watch and Band are Not Included!
- How to Check Compatibility: 1. Locate your model number (e.g., GA-110) on the backplate of your watch. 2. Measure the lug width (L) – the internal distance between the strap arms. If it measures 16mm, this case is a suitable match.
- Material: These adapters are crafted from tough ABS material, offering a lightweight yet durable solution. Each set includes spring pins and installation tools for quick and easy setup. Ideal for situations where your strap is still intact but the connector needs replacing.
Buying an original system second-hand
Ask for photographs and exact measurements before paying. A complete kit should normally include:
- Both Sinn-side shortened strap sections.
- Both Apple Watch-side sections and the correct connectors.
- The bridge strap for separate use.
- Correct spring bars and the strap tool, if completeness matters.
- The storage case, if advertised as a complete set.
Inspect rubber or silicone for cracking, hardening, stretching and chemical degradation. Confirm the Sinn’s lug width and the Apple Watch’s exact case/connector family. A partial kit can be difficult to complete because proprietary shortened sections may no longer be available.
Installing spring bars incorrectly can scratch lugs or compromise security. If you are not comfortable with spring-bar tools, use a competent watchmaker. Do not assume any adapter preserves the watch’s water resistance; that requires model-specific manufacturer confirmation.
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- Fitment: The watches adapters set is compatible with smartwatches with 18-22mm interfaces. Please confirm the size before selecting the 18mm to 22mm watch band adapter to obtain a suitable matching effect and a pleasant use experience
- Stylish Appearance: Our watch band adapter features a low-key black color, and the switch spring bar adopts glossy silver. These 2 colors of pin watch band adapter complement each other, adding a fashionable charm to the smartwatches
- Electroplating Process: Watch band adapters adopt electroplating process, which can protect the internal metal. Watch strap adapters can maintain stability in water, allowing you to enjoy water activities without taking off your watch
- Easy to Install: Metal watch band adapters are easy to install and remove, helping to save your time and energy. This watch band adapter set includes 2pcs adapters and 2pcs spring bars, making it convenient to assemble a watch strap
- Metal Material: The watch strap adapter is made of metal material, with a sturdy structure that is not easily damaged during daily use. Metal watch band adapter is able to help maintain stable strap connection and extend usage time
A modern alternative: Smartlet
Smartlet’s own 2026 guide describes a similar adapter using one continuous strap. It specifically discusses the Sinn 103’s 20 mm lugs and current Apple Watch connector families, and recommends placing the Apple Watch on the inner wrist. Smartlet lists Classic, Shadow and Titanium versions at €299, €399 and €549 respectively in that guide.
Those are vendor claims and vendor prices, not independent test results. Verify the exact Sinn case geometry, Apple Watch size, connector, comfort, durability and sensor performance before purchase. Smartlet is not documented as made or endorsed by Sinn or Apple.
Other practical choices
- Two wrists: Usually the least compromised option for comfort, Apple Watch controls and sensor contact.
- Apple Watch alone: Best for workouts, sleep and health functions, but without the mechanical-watch experience.
- Sinn alone: Cleanest and lightest option for readers who mainly want the traditional watch.
- Carry the Apple Watch separately: Can work for occasional notifications, but sacrifices wrist-based sensing and glanceability.
Who should consider dual wear?
The original system makes sense mainly for a collector who wants a period-correct Sinn accessory, owns a 22 mm Sinn and an older 38 or 42 mm Apple Watch, and accepts used-market uncertainty. A current Apple Watch owner, a 20 mm Sinn owner, or anyone prioritizing sleep tracking, low weight, tight cuffs or a large diver will usually be better served by a modern, confirmed adapter—or two wrists.
In short, the Dual Strap System was clever but niche. It solved the “mechanical watch versus smartwatch” choice with a specialized combined band, but its documented compatibility is old and its current official availability is unclear.
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Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
