MetroFlash Echo Bluetooth Smart Heart Rate Monitor Wrist Band Accurate Live Heart Data is Compatible w/Countless Mobile Health/Training Apps Fully Self-Sufficient Design Requires NO Unwieldy Chest Straps or Ancillary Sensors 10-Meter Bluetooth Range Syncs to Variety of Devices Including Apple & Android Durable Construction Ensures 10-Meter Waterproofing & 1-Meter Drop Resistance Rechargeable Lithium-Ion Battery Powered Sensor for 10 Hours Between Charges