Track bike speed, pedal rotation (cadence) and lifetime mileage of your road or mountain bike. * iPhone and iPad Compatibility - the Blue SC connects wirelessly via Bluetooth Smart (4.0) to your iPhone 4S and 5, 5C, 5S and iPad 3rd and 4th generations * Works with the most popular cycling Apps on the market today such as Strava, Cyclemeter, MapMyRide, Runtastic Road Bike, Wahoo Fitness and Wahoo Odometer (both Free on the App store) and more * Runs on a replaceable coin cell battery and requires no charging between rides for up to 1 year