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Say hello to accuracy2
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ONEOF Accuracy Logo

The most advanced watch measurement tool on iOS.
Swiss Made, like your watch.

Timing is our strength. Simply take care of your watch.

For several years, we have been developing the most accurate and precise diagnostic instruments to fulfill the highest requirements of Swiss Watch Manufactures. Today, ONEOF® accuracy gives watch aficionados the opportunity to acquire the only high-end integrated tool capable of providing a complete diagnosis of a mechanical watch on iPhone & iPad.

They talk about it.

“I tested one out for a few days and was impressed with the results.”

Stephen Pulvirent

Bloomberg Business

“Its beautiful brushed surface looks fantastic, and the app that accompanies it is similarly slick. It looks luxurious, and is priced accordingly.”

Aaron Berlow


“ONEOF Accuracy, un appareil de mesure précis, hautement technologique, au design et à la réalisation haut de gamme.”

Jérome Burgert

Les Rhabilleurs

“The achievement of such successful harmony between form and function is definitely praiseworthy.”

Marco Gabella


Dragonfly Technology. Every sounds count.

ONEOF® accuracy is made of an ultra sensitive sensor which is capable of detecting every single vibration in the movement of a mechanical watch. Each of these small vibrations is converted into a weak audio signal, highly amplified and transmitted to the iPhone. This signal is then analyzed in realtime by complex algorithms which processes tens of thousands of data every second.

ONEOF picto Calibrated


We calibrate each accuracy sensor with our dedicated instrumentation based on several atomic clock timebases.

ONEOF picto plug & play

Plug & play

Accuracy is a stand-alone device. It requires no battery or power supply. Plug it & forget it. It is that simple.

ONEOF Ressence

They love it.

Radically different from anything before it.

Accuracy had to be elegant, attractive, contemporary, easy to use, and deeply technical and performant. We considered every element. We had months of reflection and sharing of experience with watchmakers, engineers, graphic and product designers. We challenged ourselves to find the perfect match. And we finally found it.

Accuracy app. Powerful.

Just place the crown of your watch against the ONEOF® accuracy sensor and touch the dragonfly button. After a few seconds of initialization, you get all the detailed technical information about your watch in a fun and user-friendly app : beats per hour, instantaneous and average rate accuracy in seconds per day, amplitude of the balance wheel, beat error, signal analyzer… You then have the possibility to save all the results in your watch’s database.

ONEOF picto Track


Track the accuracy of your watch over its entire power reserve with our ultra-low energy consumption background mode.

ONEOF picto Save


Save the results of all of your watches in a dedicated and integrated database directly within the app.

ONEOF picto Share


For the very first time, a watch measurement instrument allows you to share your results on social networks or by email.

Discover the Accuracy App

Accuracy App

It may be all about performance, but it has emotion.

Made of anodized 6000 series aluminium unibody, the sensor has been designed with the utmost care and every detail has been perfected in conjunction with the best Swiss watch suppliers. Compared to any other measurement instruments, the high-end finishing of the accuracy sensor will definitely be consistent with your timepiece.

Get your ONEOF Accuracy Sensor

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