Withings Pulse O2 | Activity, Sleep, and Heart Rate + SPO2 Tracker for iOS and Android, Black WARNING: This product is not waterproof or sweatproof Activity tracking: steps, elevation, distance, running and calories burned Wear it your way: clip and wristband included Vital signs reading: instant heart rate and blood oxygen level Sleep monitoring: sleep cycle analysis, wake-ups, total duration.Real-time coaching: in the free Health Mate app (iOS/Android) It usually takes 1-2 hours to charge an empty battery. When turning on the device after charging, please press and hold the button for 15 seconds.If the device still won't turn on after charging, there may be an issue with the micro-USB cable try charging it with another cable Troubleshooting steps available in the user manual