Industry News
Quick Verdict
The battery number is real and it is the reason to care. Fourth Frontier launched the Frontier X3 on October 5, 2026, and its own product page claims up to four months of use at around an hour of recording a day, or up to 14 days recording continuously. The X2 it replaces is rated at 14 days on that same one hour a day pattern, and 24 hours continuously. That is the difference between a strap you charge every other week and one you charge a few times a year. The X3 also drops to 23 grams, loses the small display the X2 carried, moves to USB-C with a full charge in about an hour, and runs Bluetooth 6.0 with up to three simultaneous connections, one phone plus two external devices.
The catch is what you give up to get there. The X3 is $649, which is $70 more than the $579 X2 on Fourth Frontier's own shop, and it removes the feature that made this line unusual. You can no longer look at the ECG. Fourth Frontier states it plainly on the X3 page: "Since ECG in our non-medical products cannot be used for diagnostic or other medical purposes, the raw ECG data is not available in the Frontier X3 device." The strap still samples ECG at 500 Hz internally and derives heart rate, HRV and breathing rate from it. You just do not get to see the trace. On top of that, the metrics most buyers are shopping for sit behind Frontier Premium at $14.99 a month or $119.99 a year. If the ECG trace is why you were buying a Fourth Frontier strap, the X3 is the wrong product in the lineup.
What Actually Changed
Strip out the marketing and the X3 is a battery and packaging revision rather than a new sensor. Fourth Frontier's page says the device samples ECG at 500 Hz internally and calculates heart rate, HRV, breathing rate and Strain from it, which is the same job the X2 does. What moved is everything around the sensor.
| Spec | Frontier X2 | Frontier X3 |
|---|---|---|
| Price on Fourth Frontier's shop | $579 | $649 |
| Battery, about 1 hour a day | 14 days | Up to 4 months |
| Battery, continuous recording | 24 hours | Up to 14 days |
| Display | Small onboard display | None |
| Charging | USB cable | USB-C, about 1 hour |
| Wireless | Bluetooth 5.0 | Bluetooth 6.0, up to 3 connections |
| ANT+ | Not supported | Not supported |
| Weight | About 10 percent heavier, per Gadgets & Wearables | 23 grams |
| View the ECG trace | Generate and share an ECG PDF | Not available |
| Apple Health named on the product page | Yes, with Google Fit | No |
Gadgets & Wearables, which covered the launch on October 5, reports the 23 gram weight as roughly 10 percent lighter than the X2 and confirms the display was removed entirely. Losing the screen is less of a loss than it sounds for most people, because the X3 keeps the vibration alerts: Fourth Frontier lists buzzes for heart rate, breathing rate and Strain ranges, which is how most users got zone feedback anyway.
The ECG Trace Is the Real Story
Fourth Frontier built its reputation on being the chest strap that records a continuous ECG rather than just a heart rate number. The X2 page still advertises "24/7 Continuous ECG during 20+ activities" and the ability to "Generate & Share ECG PDF", with detailed reports available from a web dashboard to pass to a doctor. That is the feature people bought it for.
On the X3, that is gone, and the company points you up the price list instead. Its X3 page says the raw ECG display feature "is available in our FDA-cleared medical device, Frontier X Plus." The reasoning it gives is regulatory rather than technical: ECG in its non-medical products cannot be used for diagnostic purposes, so the company no longer shows it.
Here is where the pricing gets awkward. the5krunner's review of the X Plus puts that device at $649 as well, holding FDA 510(k) clearance K240794, and notes it requires a prescription, either one you already have or one arranged through Fourth Frontier's physician network at checkout. So the X3 and the X Plus cost the same money. One of them shows you the ECG, in CSV, EDF and PDF according to that review, and one of them does not. The difference is the prescription step. If you are buying for heart data you can take to a cardiologist, the X3 is the model that cannot do it, at the same price as the model that can.
For context on how consumer ECG hardware generally handles this, our guide to at-home ECG devices covers which ones are cleared for what and what the readings are good for.
What Frontier Premium Costs
Fourth Frontier's subscription page lists Premium at $14.99 a month or $119.99 a year, a saving it puts at 33 percent, with a 7 day risk free trial available once per user. Premium unlocks the metabolic profile covering VO2 Max and ventilatory thresholds, the VT zones, the Readiness Score built from HRV against your baseline, sleep stage analysis and oxygen uptake. Left free are heart rate, breathing rate, HRV, Strain, training load and a basic VO2 Max figure.
the5krunner made the sharp observation about this model when reviewing the Frontier Zone: none of the paid features need extra hardware. As that review puts it, "They are algorithmic outputs from the ECG data the device already collects." That is a fair description of most wearable subscriptions, and worth knowing before you treat the hardware price as the price.
| Setup | Hardware | Premium | Year one | Two years |
|---|---|---|---|---|
| Frontier X3, no subscription | $649 | None | $649 | $649 |
| Frontier X3 with annual Premium | $649 | $119.99 a year | $768.99 | $888.98 |
| Frontier X3 with monthly Premium | $649 | $14.99 a month | $828.88 | $1,008.76 |
| Frontier X2 with annual Premium | $579 | $119.99 a year | $698.99 | $818.98 |
Fourth Frontier was running a 30 percent launch discount with the code LAUNCH30 when we checked the X3 page on October 6, 2026, which takes the strap to $454.30. Launch codes expire, so treat $649 as the number to plan against and the discount as a bonus if you catch it. One detail from the subscription page is easy to miss: Premium features apply only to activities recorded after the subscription starts, so subscribing later will not retroactively score the training you already did.
No ANT+, on Either Generation
Both the X2 and the X3 product pages state that ANT+ is not supported. The X3 connects over Bluetooth 6.0 to as many as three devices at once, which Fourth Frontier describes as one phone plus two external devices.
For most people this is fine. Garmin watches, Apple Watch, Zwift, Peloton and Wahoo head units all take a Bluetooth heart rate strap. The X3 page names Garmin, Strava, Coros, Zwift, Peloton, Whoop, Wahoo and TrainingPeaks among the things it works with. Where Bluetooth only still bites is ANT+ only equipment. If your bike computer, treadmill or gym machine takes ANT+ and nothing else, no Fourth Frontier strap will pair with it, and that has been true across the range rather than being a new X3 limitation.
Where the Data Can Go, and What We Could Not Confirm
This is the part we want to be careful about, because the two product pages do not say the same thing. The X2 page lists integration with "Apple Health, Google Fit, Strava, TrainingPeaks, Zwift, Wahoo, Garmin and more." The X3 page lists Garmin, Strava, Coros, Zwift, Peloton, Whoop, Wahoo and TrainingPeaks, and when we read it on October 6, 2026, the words Apple Health, Health Connect and Google Fit did not appear anywhere on it. The page does say the apps are "iOS, Android & web dashboard."
We are not going to tell you the X3 dropped Apple Health support, because a page not mentioning something is not the same as a company removing it, and Fourth Frontier may simply have written a shorter integrations list for a new product. What we can tell you is that the X3's path into your phone's health platform is not documented on the page where you buy it. If getting Frontier data into Apple Health on an iPhone, or into Health Connect on Android, is part of why you are buying, ask Fourth Frontier support to confirm it in writing before you order rather than assuming the X2's list carries over.
That matters more than it used to, because the phone health platform is how most third party apps see your data at all. Our write-up of Garmin and Health Connect shows how specific these gaps get: a company can support a platform in general and still withhold the exact metric you wanted.
Who Should Buy It
Buy the X3 if you want continuous heart rate, HRV, breathing rate and Strain from a chest strap, you already know you prefer a strap to a wrist sensor, and the thing that has annoyed you about chest straps is charging them. Months between charges is a genuine change in how you live with the device, and 23 grams with no screen is about as unobtrusive as this category gets. On those terms it is a good product.
Do not buy it for the ECG. The X3 is the model in this lineup that will not show you one, by the company's own statement, and the X Plus costs the same with a prescription requirement attached. Think twice too if the budget is tight, because the X3 is $70 more than an X2 that still shows the ECG PDF, and the headline metrics on both need $119.99 a year on top. For people who mainly want recovery and training load without a subscription, there are cheaper straps and bands; our comparison of a subscription free strap against WHOOP covers that end of the market.
One honest limitation on this article: we have not worn an X3. Everything above comes from Fourth Frontier's own pages and from two publications that cover this category closely. Battery claims in particular are the kind of number that deserves a real-world test before you treat it as settled.
Where Vora Fits
Vora is our app, and it has no direct Fourth Frontier connection. Vora connects directly to Oura, Garmin, Fitbit and WHOOP (beta) on iPhone and Android, plus Samsung Health on Android. Fourth Frontier is not on that list, so a Frontier X3 would have to reach Vora the way most other devices do, through Apple Health on iPhone or Health Connect on Android.
As described above, we could not confirm from Fourth Frontier's X3 page that the strap writes to either platform, so we are not going to promise that route works. If it does, the metrics worth having are the ones Vora already builds on: heart rate, HRV and breathing rate. Reading your health data is free on every Vora plan, including the direct connections.
Two limits to state plainly. Vora calculates its own Sleep and Recovery scores and does not import other companies' scores, so a Frontier Readiness Score stays in the Frontier app even if the underlying data arrives. And Vora cannot see anything the Frontier app does not write out, so a metric sitting behind Frontier Premium is not something Vora can reconstruct. Our integrations page lists what connects today, and Vora on Android covers the Health Connect side if that is the phone you carry.