You love your mechanical watch. You also want to track your sleep, heart rate, and workouts without strapping a second device to your other wrist or giving up the watch you carefully curated.
This is the tension that has defined watch collecting for the last decade. And it’s the exact problem the XBAND smart strap is trying to solve.
Instead of cramming electronics into a watch case, XBAND hides them inside the clasp of an FKM rubber strap. The watch stays pure. The strap does the work.
XBAND Smart Strap – Health tracking clasp for 20mm mechanical watches
VIP Early Bird Price: $279 (30% off $398 MSRP)
Replacement Straps: $89 each – black, white, orange, green
$1 Deposit secures VIP early bird pricing
Where to Buy: Kickstarter
Meet the XBAND Smart Strap
XBAND is a 20mm FKM rubber watch strap with a deployant clasp that contains a full sensor suite. It’s made by Codex, a Hong Kong-based company, and replaces your existing watch strap entirely. Inside the clasp: a Goodix GH3026 PPG sensor for heart rate and blood oxygen. A Bosch BMA400 accelerometer. An NTC temperature sensor. A Nordic nRF52840 processor with 4MB of flash. All of it 316L stainless steel.
The strap attaches to any watch with 20mm lug width, which covers the majority of modern mechanical watches. It’s cut-to-fit, like a Patek Philippe Aquanaut strap, so you trim it to your wrist size and then click the clasp. A snug fit keeps the sensor pressed against the underside of your wrist for more consistent readings.
The strap comes in four colors: black, white, orange, and green. Replacement straps without the smart module cost \$89 each. That makes color swaps affordable without buying the whole clasp again.
The Idea That Finally Works
The smart strap concept has been tried before. Sony tried it with Wena. MMT tried it with the E-Strap. None of them gained traction, partly because the technology was early and partly because the execution was never this polished.
XBAND is different for a few reasons. The sensor module lives inside the clasp, not in a bulky buckle or separate pod. The FKM rubber matches high-end OEM straps. And the sensor package is genuinely capable. A Goodix GH3026 is the same component used in the Samsung Galaxy Fit 3. Not some off-brand part.
For mechanical watch fans, this means you can wear your Submariner, your Speedy, your Black Bay, or your favorite microbrand diver and still get health tracking data without double-wristing. No Apple Watch on the other arm. No Whoop band jammed next to your watch head. One wrist, one watch, one strap that happens to be smart.
The Wellness Features It Claims to Track
Based on the official specs from Codex and the XBAND product page, here’s what the strap claims to track:
- Heart rate (continuous)
- Blood oxygen (SpO2)
- Sleep (duration, stages, efficiency, sleep debt)
- Stress (via heart rate variability)
- Activity (steps, distance, calories)
- Blood pressure trends
- Glucose trends
- Women’s health tracking
- 40+ sports modes
- Mood insights based on physiological patterns
- AI-powered workout insights and recommendations
The strap syncs with the XBAND app for iOS and Android. Data also syncs to Apple Health and Google Health if you use those ecosystems.
Worth flagging: blood pressure and glucose trend tracking are claimed features. The sensor can estimate trends, but this isn’t the same as a medical-grade blood pressure cuff or a continuous glucose monitor. Codex’s own app store listing says the app is “intended for general fitness and wellness purposes only and isn’t designed for medical diagnosis or treatment.” That’s the right disclaimer, and we should take it seriously.
How It Attaches to Traditional Watches
The strap uses standard spring bars and works with any watch that has 20mm lug width. You remove your existing strap, attach the XBAND strap using quick-release spring pins, trim it to your wrist size, and you’re done.
The clasp itself measures 44mm long and 18mm wide. Codex says it uses 316L stainless steel, Swiss-crafted. The strap weighs 37.5 grams, which is roughly what a typical rubber strap with a steel clasp weighs.
Water resistance is 50 meters. Fine for swimming and showering. Not for diving. Most mechanical dive watches can go deeper, which means the strap becomes the weak point.
The Big Questions
Accuracy
Nobody outside Codex has independently tested the XBAND’s sensor accuracy. The Goodix GH3026 is a respected optical sensor used in mass-market wearables, but its accuracy depends heavily on fit, placement, and algorithm tuning. A strap that shifts during a workout will produce different readings than one that stays locked in place. The cut-to-fit design helps, but we need to see third-party testing before making strong claims.
Battery Life
Codex claims 7+ days on a 23mAh battery, with a 1.5-hour recharge time via magnetic USB-C. That’s competitive with the Whoop 4.0 and better than most full smartwatches. The trade-off is that you’ve to take the strap off to charge it, which means you lose sleep tracking on charging nights unless you charge during a shower or desk time.
App Quality
The XBAND app is live on iOS App Store and Google Play. Version 1.0.3 shipped just hours ago. The iOS version requires 15.6 or later. Under the hood it’s developed by “dishi wen” under Codex Inc. Here is the important part: it’s currently Simplified Chinese only. An English version is expected by the time the product ships but hasn’t been confirmed.
Compatibility
20mm is the most common lug width. It isn’t universal. Watches with 18mm, 19mm, 21mm, or 22mm lug widths won’t fit the standard XBAND strap. Codex doesn’t list additional size options today. The Kickstarter campaign may fund future variants.
The sensor sits under the wrist, which works well for most people. But if you wear your watch loose or prefer a bracelet that allows the watch to slide around, the sensor data will be unreliable. The cut-to-fit design requires a deliberate sizing decision.
Privacy
Codex publishes a privacy policy stating that health data is encrypted, not shared with third parties, not sold to advertisers, and that users can update or delete their data. The policy also says the product isn’t intended for users under 18. This is a solid baseline, but the company is new, and privacy policies only matter as much as their enforcement.
This Is for
Mechanical watch enthusiasts who want health tracking without wearing two devices. Collectors who rotate watches and want a strap that can move between their 20mm pieces. People who already wear a fitness band under their watch and want a cleaner setup. Anyone curious about the smart strap category and willing to back a first-generation product.
This Is Not for
People who need 22mm or non-standard lug widths. Anyone looking for FDA-cleared health monitoring. English-only speakers until the app language situation is clarified. Buyers who want a sealed, tested product rather than a crowdfunding campaign. Watch owners who swim or dive deeper than 50 meters.
How It Compares
This isn’t a full comparison piece, but context helps. Where XBAND sits:
Apple Watch: XBAND has no screen, no notifications, no GPS, no cellular. It doesn’t try to replace a smartwatch. It adds health tracking to an analog watch experience.
Whoop: XBAND is a strap for your existing watch. Whoop is its own wearable. XBAND wins on aesthetics and watch compatibility. Whoop wins on subscription data and a proven platform. Different tools. Different jobs.
Oura Ring: Same concept. Health tracking with no screen. But on the wrist, not the finger. Oura has more sleep research behind it. XBAND has the watch audience alignment.
Hybrid watches (Withings, Garmin Vivomove): Hybrids replace your watch. XBAND works with the watch you already own.
Previous smart straps (Sony Wena, MMT E-Strap): XBAND has better sensors, a more modern component set, and a significantly more practical clasp integration.
XBAND Smart Strap – Smart clasp for traditional watches
Early Bird Price: $279 | MSRP: $398 | Save 30%
Replacement Straps: $89
Buy Now: Kickstarter
Final Verdict
The XBAND smart strap is the most compelling version of a concept that has been kicking around for years. The component choices are solid. The clasp integration looks genuinely well-engineered. The FKM rubber and 316L steel match the quality level of the watches it’s designed to complement.
The open questions are the usual Kickstarter unknowns. Does the battery hold up in real use? Is the app ready for English speakers? Does sensor accuracy match the features? Nobody outside Codex has tested this yet. None of these are dealbreakers, but they’re reasons to treat this as an early adopter product rather than a mature purchase.
For the watch collector who has been double-wristing with a fitness band or wanting to, the XBAND is worth a serious look. It’s the first product that understands the mechanical watch fan’s actual relationship with their watches: you don’t want to replace them. You want to keep wearing them. You just want a little more data from the wrist they’re already on.
Elegance intact, intelligence inside. That’s the pitch. And for the first time in this category, the product actually delivers on it.
Feature Summary
| XBAND Smart Strap – Specifications | |
|---|---|
| Sensor Module | Goodix GH3026 PPG, Bosch BMA400 accelerometer, NTC temperature sensor |
| Processor | Nordic nRF52840 with 4MB flash |
| Battery | 23mAh, 7+ days life, 1.5h recharge via magnetic USB-C |
| Clasp Material | 316L stainless steel, Swiss-crafted |
| Strap Material | FKM rubber, cut-to-fit |
| Lug Width | 20mm |
| Clasp Dimensions | 44mm x 18mm |
| Weight | 37.5g |
| Water Resistance | 50m |
| Connectivity | Bluetooth 5.x |
| App | iOS 15.6+ and Android, Apple Health + Google Health sync |
| Colors | Black, white, orange, green |
| Pricing | $279 early bird (30% off $398 MSRP), $89 replacement straps |
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(as of July 10, 2026 17:13 GMT -05:00 - More infoProduct prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on [relevant Amazon Site(s), as applicable] at the time of purchase will apply to the purchase of this product.)
