Integrated speed and cadence sensor that wirelessly transmits ANT+™ and BLE 4.0. signals to your computer or phone. Easy install, directly into the chainstay of bicycles. Accurate speed and cadence measurement. Compact & slimline design. Universal fit & easy installation. BLE 4.0 and ANT+™ wireless technology. Works with most apps, smartphones, watches and cycle computers. Replaceable CR2032 coin cell battery lasts up to 20 months.