Shop Suunto Smart Sensor(Ambit3 Peak and Sport Only). 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 Movesense compatible sports apparel.