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Review: The MMT E Strap Can Turn Any Watch into a Smartwatch

Is it the perfect smartwatch for watch enthusiasts?

Henry Phillips

Earlier this year, I tested two hybrid smartwatches and found that, overall, it’s a promising concept still in its teething stages. If you’re looking for basic notifications and smart tracking capabilities, or, more importantly, better-looking wrist wear, it’s great. Want third-party apps? Well, you’re barking up the wrong tree.

That’s the problem with a nascent market: You have very limited options. That’s not a dig at the existing players, but if hybrids are meant to rectify the decidedly unstylish look of a standard smartwatch, you’d hope for more variety. One of those watches was Frederique Constant’s “Horological Smartwatch” — which is a bit of a misnomer given that it’s powered by quartz. That’s certainly not going to win over any mechanical watch diehards. But a vintage dive watch or a tourbillon that could track your steps? That certainly would. Fortunately, with MMT’s new E-Strap, that’s 100 percent possible.

The smart strap solution — which makes it possible to turn any watch into a smartwatch since all the tech is confined to just the strap — has been kicking around for the last couple years. There are numerous Kickstarters out there, IWC seemingly toyed with the concept and Montblanc debuted their own connected strap, though you have to purchase an entire watch just to get it. Sinn even seemingly gave the concept a try by slapping an Apple Watch onto the strap of one of their mechanical watches — a solution so endearingly ill conceived I can’t help but crack a smile. But MMT’s E-Strap is perhaps the concept in its most tangible, realized form.

The secret is the buckle, which houses the battery and sensors. It’s about the size of a Starburst and completely hidden by leather when worn. The rest of the strap is standard, and there’s no way for anyone to know you’re wearing anything other than a regular watch. Yet despite its size, the strap is capable of working continuously for a whole week before it needs to be charged, a process about as simple as it gets: simply nestle the buckle into its charging dock and wait a few hours.

Unsurprisingly, due to its limited size and wrist placement, there isn’t much in the way of features. The E-Strap uses the same app as the Horological Smartwatch, but there are no notifications or alerts and no world time function. You also need to check the app to see your goal progress (the Smartwatch showed daily goal progress on an analog dial). What the strap can do is track your steps, calories, and your sleep. Some would call it watered down, but the features I found most useful in the original Horological Smartwatch were sleep- and fitness-tracking, anyway.


The E-Strap is easy to use. Setting it up is as simple as turning on your phone’s Bluetooth and pressing the discreet button on the side of the buckle. After that, syncing data is done automatically (many other Hybrids require pushing the watch’s crown in). The app is simple and intuitive, displaying sleep and step goal progress on the home page. Still, some might be disappointed with the strap’s lack of ability. It’s pretty widely accepted that heart rate monitoring is an essential component in fitness tracking, and some might consider the whole exercise redundant given that fitness-tracking and sleep-tracking apps are readily available on a smartphone.

But here are some things to consider: Most people don’t need detailed fitness data unless they’re dedicated athletes (which you probably aren’t if you’re wearing a mechanical watch while working out), and most smartwatches and wearables are already deemed redundant by smartphones, anyways. Further, a wearable fitness tracker allows you to ditch the phone at home for runs and pensive strolls.

The possibility of the conecpt itself is wonderful and far more conducive to habitual wear if you’re a watch enthusiast.

That said, I’m not willing to write off the E-Strap as a total success. For starters, it’s only available in leather, which is very nice, but uncomfortable during a run or while sleeping. MMT/Frederique Constant/Alpina would be wise to consider offering a rubber strap version. Further, Alpina only offers 22mm wide straps, and Frederique Constant’s dressier options only come in 22mm and 20mm lug widths, so the dream of turning any watch into a hybrid smartwatch is unfulfilled until more strap sizes become available. And if heart rate monitoring were able to be incorporated without sacrificing battery life (the reason MMT currently doesn’t offer it), it would be game changing.

Still, this is relatively uncharted territory, and my hope is that these fixes will eventually be addressed. But the possibility of the concept itself is wonderful and far more conducive to habitual wear if you’re a watch enthusiast. When I was testing the standard hybrid smartwatches from Frederique Constant and Timex, I wasn’t as smitten with the watches themselves as I was my own collection of watches, and there was a temptation to wear my own watches in place of the hybrid. Given that the E-Strap I received came affixed to a handsome, vintage-style dive watch, I didn’t have that problem at all.

Buy Now: $194

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