Monitor your pedalling cadence as you ride with this easy to install wireless sensor simply attach the sensor and ride with no magnets or other exposed parts to line up this sensor is easy to install maintain and move between bikes the cadence sensor fastens to any crank arm size and measures pedal strokes per minute so you can get the most out of your training available separately the speed sensor attaches to the hub of either wheel and self calibrates with your edge to give you accu