S1 Companion 4+

Push the boundaries of your performance with the world’s most accurate sweat sensor.


The S1 gives you an unprecedented understanding of your body’s hydration needs for training and race day. It measures your water and electrolyte losses in real time, with an accuracy on par with in-field gold standards. The S1 is trusted by WorldTour Cycling teams and Olympic Gold medal triathletes.


The S1 Companion App ensures you get the most out of your S1 device:
- Understand your sweat composition for a session and view your hydration recovery plan.
- Study your previous sessions with our insights tool. We will show you your hydration problem areas and provide tailored recommendations on how to improve.
- Prepare for your upcoming sessions using our Planner tool. Input the details of your upcoming session or race, and we’ll leverage your past data to predict your expected fluid and sodium losses to help inform your hydration strategy.
- You can connect your favourite fitness apps and devices, including Garmin, Wahoo, Zwift and Coros - we’ve got you covered.