Wahoo RPM Sensor for iPhone, Android and Bike Computers
Track and capture real-time cycling cadence on your iPhone, Android, and bike computer.
Lightweight and easy to install - NO MAGNETS. Easily attaches to your bike's crank arm or shoe - (both mounts included).
Connects wirelessly via Bluetooth 4.0 and ANT+ to your iPhone, Android and/or bike computer.
Works with Zwift and TrainerRoad!  Capture cadence on your favorite indoor cycling platform.
Also works with the free Wahoo Fitness app, Strava, RideWithGPS, MapMyRide, Cyclemeter, and more!