4iiii Viiiiva 2.0 Heart Rate Monitor: All you need to know

Launched on 26 February 2026, the 4iiii Viiiiva 2.0 is a chest-strap heart rate monitor priced at £64.99 in the United Kingdom ($99.99 in the US). It is made by 4iiii Innovations of Alberta, Canada, whose founder, Kip Fyfe, led the team at Dynastream that invented the ANT+ wireless protocol, a business subsequently acquired by Garmin.

The Monitor

Dual ANT+ and 1x Bluetooth Low Energy transmission makes the Viiiiva 2.0 compatible with any modern bike computer, watch, or training app. A circular sensor pod slides onto two steel connector pins on the chest strap and must be worn with the arrows facing upward; an inverted pod will produce inaccurate readings.

Power comes from a pre-installed CR2032 lithium coin cell rated at 540+ hours. 4iiii advises against cells with a bitter coating, which testing has shown to be non-conductive and a cause of connection dropouts; bare-hand contact with a new battery should also be avoided.

The battery cover requires a flathead screwdriver to open. IPX7 waterproofing is rated to ten metres, though the cap should be kept dry during battery changes. The strap is hand-washable with mild soap and water; machine washing damages the sensors.

Specifications

• Price: £64.99 inc. VAT (UK) / $99.99 (US)
• Hardware revision: Viiiiva 2.0, January 2026
• Chest strap size: 66–132 cm (26–52 inches)
• Heart rate range: 30–240 bpm at 1 bpm resolution
• Transmission: ANT+ and Bluetooth Low Energy
• Battery: CR2032 lithium coin cell (pre-installed)
• Battery life: 540+ hours
• Auto power-down: 3 minutes
• Waterproof rating: IPX7 to 10 metres
• Data transmission range: 3 metres
• Operating temperature: 0–50°C
• Storage temperature: –20 to 70°C
• Frequency: 32.768 kHz
• Input sensitivity: 5% duty cycle
• Weight: Under 46 g

Competitor Comparison

Background: The Original Viiiiva, 2012–2025

Continuous production since 2012 makes this one of the longer-running products in cycling tech. At launch, cycling sensors communicated almost exclusively over ANT+ while smartphones were adopting Bluetooth Low Energy — and the original Viiiiva was the first device on the market to receive ANT+ signals from paired third-party sensors and rebroadcast them as a Bluetooth signal, sparing athletes from replacing functional equipment to use mobile training applications.

Early hardware also offered onboard caching of up to 65 hours of activity data, beat-to-beat measurement precise enough to support heart rate variability analysis, and tap-to-pair connectivity. Battery life was rated at 200 hours. Neither the protocol conversion nor the onboard logging features carried over to the 2.0. What has changed is battery life, extended to 540+ hours, and a simplified, more durable hardware design. The name is a play on the Roman numeral VIII, a nod to the company identity as 4iiii.

The 4iiii Product Range

Alongside the Viiiiva 2.0, 4iiii produces the Precision 3+, a single-sided crank-arm power meter using strain gauge technology, and the Precision 3+ Pro, which extends this to a dual-sided system for left-right power balance, interestingly with Apple FindMy compatibility. A sustainability initiative, Ride Ready reCYCLED, offers refurbished cranksets with power meters factory-installed. 4iiii Ride is the company’s companion app for in-ride data and coaching integration.

Take Out

The strap, as described at launch, has very run-of-the-mill features. Only the 540-hour battery stands out.

I would caution anyone against wearing a chest strap rated IPX7/10m for swimming. They should be fine, but in my experience, none are. Though if you plan to wear one under a wetsuit twice a year for a race, that’s probably Ok.

More: Product Manaul

Price correct at time of publication. UK pricing includes VAT. Shipping calculated at checkout. Available direct from the 4iiii UK store and via authorised dealers.

Last Updated on 26 February 2026 by the5krunner

the5krunner

tfk is the founder and author of the5krunner, an independent endurance sports technology publication. With 20 years of hands-on testing of GPS watches and wearables, and competing in triathlons at an international age-group level, tfk provides in-depth expert analysis of fitness technology for serious athletes and endurance sport competitors.