Bike Speed Sensor 2 & Cadence Sensor 2 Size:One Size Keep their water colder Meet a shoe that Keep their water colder Features Music distance and cadence data to compatible training apps or displays by using ANT+®connectivity and Bluetooth® Low Energy technologyWith both of these sensors on your bike maintain and move between bikesThe Speed Sensor 2 attaches to the hub of either wheel and self calibrates with your Edge® cycling computer or compatible Garmin device to give you accurate speed and distance at all times — even without a head unitThe Cadence Sensor 2 fastens to any size crank arm and measures pedal strokes per minute so you can get the most out of your trainingSend live speed