Improve Cycling EfficiencyThe S3+ dualmode sensor displays and records the bike's speed index, cadence data, helps you ride in the best condition. If you want to have both cadence and speed data at the same time, two sensors are required. ANT+ and Bluetooth 4.0 The sensors are compatible with all devices that support standard ANT+ protocols . Bluetooth works with Strava, SUUNTO sports watches, etc. It will work with an iPhone, Android device or bike computer. (Please confirm the compatibility of smart devices/apps you use before purchasing) Dual Speed & Cadence Mode Simply reinstall the battery to switch between speed and cadence mode. The Speed Sensor mounts to the wheel hub of any bike and the Cadence Sensor easily attaches to your bike's crank arm, providing you with accurate data. Attention: A sensor can only select one mode (speed or cadence) at a time. Lightweight and Geomagnetic SensorWeight only 8.8g (with battery), does not affect appearance of the bike and increases the riding load. Easily attaches to your bike with the included rubber snap rings (two sizes). IP66 water rating, waterproof, dustproof. Track cadence and speed by terrestrial induction, NO magnet needed. Supports Different Device Dual Protocols & Long Battery LifeANT+ records data simultaneously with sports app. S3+ can link ANT+ bike computer, watch and APP with your phone, record multiple data at the same time, so you can view and share it in different ways. Autonomy from 400 h to 500 h Battery life.