Size really matters. Whatever your sport, Suunto Smart Sensor – the smallest Bluetooth Smart compatible heart rate sensor on the market – measures your heart rate with great comfort and accuracy. While swimming, the sensor stores your heart rate data and transfers it wirelessly to your Ambit3 watch or Suunto Movescount App. Pairing the sensor with the free Suunto Movescount App, you can also analyze, relive and share your moves to make every move count. The Suunto Smart Sensor comes with a redesigned heart rate belt, and can also be used on its own when attached to compatible sports apparel.