Wahoo SC Speed & Cadence Sensor BLE & ANT+A fantastic sensor that is easy to use which will provide you with all the information and metrics that you need to improve and track your cycling performance TechThe device works by connecting, wirelessly, to your smartphone (either iOS or selected Android) and syncs the information recorded by the sensor to your Wahoo Fitness App. You can also submit and track the information via compatible apps such as: Cyclemeter, Strava, MapMyRide, and Runtastic Road Bike. The SC Sensor collects these metrics via the rear chain of your bike using spoke and crank magnets to track bike speed and pedal rotations per minute. Wahoo claim that this is a more accurate method of recording that GPS based speed and distance sensors MetricsTo help you boost your cycling performance the Wahoo SC Sensor will help by providing you the metrics you need to really track your progress. The Sensor tracks:Bike speedPedal rotation (cadence)Lifetime mileageFeaturesRubber band mounting system providedHas a small and low drag profileBluetooth and ANT+ compatibleReceives signal up to 10 feet away100% waterproof up to 5ftComes with replaceable CR2032 coin cell batteryWeighs 36gFits a wide majority of bike framesBuy Wahoo Activity Monitors from Chain Reaction Cycles, the World’s Largest Online Bike Store.