| General | |
|---|---|
| Manufacturer | Fourth Frontier |
| Type | Prescription ECG chest strap (FDA-cleared medical device) |
| Series | Frontier |
| Released | FDA 510(k) clearance announced in 2025 |
| Price at launch | USD |
| Predecessor | Frontier X2 (the medical branch of the range). See the Frontier X2 specifications. |
| Successor | Not yet announced |
| Weight | 25g |
Specifications and features as at launch.
Jump to: Expert opinion | What’s new | Specifications | Battery life | Features | Further reading
Expert opinion
The Frontier X Plus is the only FDA-cleared device in the range, cleared under 510(k) for ambulatory ECG monitoring. It is built for people who already have, or are being investigated for, a heart condition, and it gives up the sports features of the X2, Zone and X3.
It streams live ECG, lets you download the ECG as a PDF and as raw data, and reports rhythm status for atrial fibrillation, bradycardia, tachycardia and arrhythmia burden. It is sold in the US only, needs a prescription, and is rated for adults aged 22 and over.
What’s different versus the Frontier X2
Hardware
- Sampled ECG at 500Hz, up from 250Hz, stored at 125Hz on both
- IP22 water resistance, down from IP67
- Connects to the Frontier Plus app only, down from three simultaneous connections
Software
- Rhythm status for atrial fibrillation, bradycardia, tachycardia and arrhythmia burden
- Weekly Cardiac Rhythm Report, on a separate subscription
- No vibration alerts, training load, Body Shock, step cadence, VO2 max, readiness or sleep staging
- No third-party streaming or app connections
Unchanged
- Pod dimensions of 73 x 24 x 13mm, 25g and a colour display on the device
- Micro USB charging and Bluetooth 5.0
- Continuous recording, up to 24 hours
Specifications
| Physical | |
|---|---|
| Pod dimensions | 73 x 24 x 13mm |
| Weight | 25g |
| On-device screen | Colour display |
| Water rating | IP22 |
| Charging | Micro USB |
| Strap | Elasticated fabric with conductive and insulating layers, REACH and RoHS compliant, standard 45mm snap spacing |
| Sensing | |
| ECG lead | Single-lead ECG, approximating the V5 position of a 12-lead ECG |
| ECG sampling rate | Sampled at 500Hz, stored at 125Hz |
| Movement metrics | Not offered |
| Connectivity | |
| Bluetooth | Bluetooth 5.0 |
| ANT+ | Not supported |
| Simultaneous connections | One: the Frontier Plus app only |
| Third-party integrations | Not supported |
| ECG access | |
| Viewing and exporting the ECG trace | ECG streaming included, with ECG PDF and raw data download, in the base device |
| Rhythm detection | Rhythm status for atrial fibrillation, bradycardia, tachycardia and arrhythmia burden |
| Subscription | |
| Optional subscription | Essential Care plan for weekly reports (Weekly Cardiac Rhythm Report) |
| Regulatory | |
| Classification | Medical device |
| FDA | FDA 510(k) cleared for ambulatory ECG monitoring |
| How you buy it | Prescription only, for adults aged 22 and over, US store only |
The X Plus is indicated for adults who are asymptomatic, or who are experiencing transient symptoms requiring cardiac monitoring. It is not indicated for ischemia or myocardial infarction, and it is contraindicated for people with pacemakers or ICDs. The Fourth Frontier website lists IP67 water resistance, where the company’s product comparison document gives IP22. This page uses the comparison document.
Battery life
| Mode | Battery life |
|---|---|
| Typical use (about an hour a day) | Around 14 days |
| Recording continuously | Up to 24 hours |
Features
Features are listed under Fourth Frontier’s own headings.
Key features
- Detect AFib early: 24/7 continuous ECG with arrhythmia burden analysis
- No adhesives or wires: designed for wear during exercise, rest and sleep
- View and share ECG reports with your physician
- Weekly rhythm insights: heart rate and arrhythmia burden over time
Validation
- Fourth Frontier’s study of 832 patients, against a 12-lead ECG, reports 98.1% sensitivity and 97.9% specificity for atrial fibrillation detection
- Detects normal sinus rhythm, atrial fibrillation, bradycardia and tachycardia
Subscription
- Optional Weekly Cardiac Rhythm Report: USD 30 a month or USD 240 a year
Further reading
Related straps
Looking at alternatives to the Frontier X Plus?
- Sports alternative: Fourth Frontier X2, which needs no prescription and adds the sports features the X Plus gives up.
- Also consider: the Polar H10. It is hardware only, so you need separate ECG software and it has none of the in-exercise features. It can record an ECG, but it is not a medical device.
