The 4iiii Viiiiva is a precision heart rate monitor designed to capture the most accurate picture of your internal physiological effort. Whether you’re pushing through a high-intensity workout, pacing a marathon, or climbing the virtual mountains of Zwift, the Viiiiva provides the real-time data needed to optimize performance, track cardiovascular fitness, and manage recovery with professional-grade accuracy.

Built for athletes of all abilities, the Viiiiva is engineered for comfort and extreme durability. With 540+ hours of battery life and an IPX7 waterproof rating, it is built to withstand the elements and your highest-intensity efforts. The Viiiiva is a reliable cornerstone of your training toolkit, providing the pulse of your performance every time you move.

Pair the Viiiiva with a 4iiii power meter to seamlessly link external output (Watts) and internal response (bpm). This combination provides a total understanding of training efficiency, allowing you to optimize training zones and track fitness gains with total precision.