Improves your cycling technique and performance Speed sensor accurately measures your cycling speed and distance, Cadence sensor measures the real-time and average pedaling rate of your ride Small and light design with firm bike attachment, Uses Bluetooth low energy wireless technology Compatible with Polar V800, Polar V650, popular cyclin apps, the iPhone 4S and later and select Android devices usin Android 4.3 or later Set includes one Polar Bluetooth Smart speed sensor and one Polar Bluetooth Smart cadence sensor Boost your cycling performance with Polar Bluetooth Smart cadence and speed sensors. Find out what your most efficient pedaling rate is and measure your speed and distance accurately. The sensors included in this set work with Bluetooth Smart technology and consume only a little energy. Light yet tough and easy to attach. Compatible with Polar V800, Polar V650, popular cycling apps, the iPhone 4S and later and select Android devices using Android 4.3 or later.