S1 — 24/7 Performance & Recovery Tracker

No screen. No distraction. Just your data.

The S1 continuously measures what decides your next fight or run: your recovery, your sleep and your training load. No screen to check, no notifications: you focus on the work, the S1 handles the numbers.

What the S1 tracks for you

• Heart rate and resting heart rate
• Heart rate variability (HRV) and stress level
• Blood oxygen (SpO2) and respiratory rate
• Detailed sleep: light, deep and REM phases, temperature during sleep
• Steps, calories, active time and VO2 max
• Heart-rate zones during training

Built for effort

• Automatic modes: the S1 detects rest, training and sleep on its own and adapts its measurement rate.
• Two ways to wear it: on the wrist every day, or on the arm with the optional armband for intense sessions.
• Multi-LED: an optical sensor with several LEDs for steadier readings.
• 10 days of battery life, magnetic charging: up to 80% in 60 minutes.
• 3 ATM water resistance, discreet vibration alarm.

F24H app, no subscription

Sleep, activity and recovery scores, 6-month trends, sync with Apple Health and Google Fit. No subscription required, no extra fees.

Specifications

• Size: 46 × 28.15 × 11.2 mm, 15.3 g
• Battery: 200 mAh, 10 days
• Data storage: 14 days
• Connectivity: Bluetooth Low Energy
• Wrist band: 145 to 230 mm, armband: 190 to 310 mm
• Operating temperature: -10 °C to 50 °C

The S1 is a wellness and training tracking tool, not a medical device.