4iiii Viiiiva Heart Rate Monitor V2 With unmatched battery life, rugged water resistance, and dual ANT+ and Bluetooth connectivity, the 4iiii Viiiiva Heart Rate Monitor V2 ensures you never miss a beat - literally. Unrivalled Accuracy for Smarter Training The Viiiiva doesn’t just track your heart rate, it reveals the true story of your effort. By providing real-time, lab-grade data, it helps you fine-tune your training zones, optimise recovery, and push your limits with confidence. For cyclists who rely on data to drive progress, the Viiiiva eliminates guesswork, allowing you to train smarter, not harder. Pair it with a 4iiii power meter to unlock a complete picture of your performance, bridging the gap between watts and heart rate for unparalleled insights into your fitness gains. Built to Endure Your Toughest Rides Athletes need gear that keeps up with their ambition, and the Viiiiva delivers. With an IPX7 waterproof rating, it shrugs off rain, sweat, and even the occasional mud splash, ensuring reliability in any condition. The 540+ hour battery life, powered by a single CR2032 coin cell, means you can focus on your training, not on charging. Whether you’re logging winter miles or tackling multi-day events, the Viiiiva is engineered to last as long as you do. Seamless Connectivity for Indoor and Outdoor Training The Viiiiva speaks the language of your devices. Thanks to dual ANT+ and Bluetooth compatibility, it syncs effortlessly with your head unit, smartwatch, or favourite indoor training app, from Garmin to Zwift. No more switching monitors or losing data; the Viiiiva ensures your heart rate is always where you need it, whether you’re grinding up a mountain pass or spinning in your pain cave. For cyclists who train across platforms, this versatility is a game-changer. Specifications Chest Size: 66 - 132cm (26” - 52”) Auto Power Down: 3 minutes Transmission: ANT+ & Bluetooth® Battery Type: CR2032 lithium-ion coin cell Battery Life: 540+ hrs Operating Temperature: 0 - 50°C (32 - 122°F) Storage Temperature: -20 - 70°C (4 - 158°F) Data Transmission Range: 3m (9.5’) Waterproof Rating: IPX7 Heart Rate Range: 30 - 240 bpm (1 bpm resolution) Input Sensitivity: 5% duty cycle Frequency: 32.768KHz Weight: < 46g (1.6oz)