Easy-to-install - Simply attach the sensors and ride. With no magnets or other exposed parts to line up, these sensors are easy to install, maintain and move between bikes. Speed sensor - Attaches to the hub of either wheel and self-calibrates with your Garmin Edge to give you accurate speed and distance at all times, including indoors on the turbo trainer. Cadence sensor - Fastens to any crank arm size and measures pedal strokes per minute so you can get the most out of your training.