Monitor your performance in real time with this Cadence & Speed Sensor pack from Garmin. With their lightweight, easy to install & wireless operation, the Garmin Speed & Cadence Sensor relay real time information right to your Garmin GPS Unit. The Cadence Sensor is designed to fit any size crank arm & accurately records pedalling strokes per minute so you can train at your optimal cadence. The Speed Sensor attaches to the hub or either wheel & self calibrates itself to your Garmin Edge to provide accurate speed & distance at all times, even when indoors on the turbo or when you lose your GPS signal. The Garmin Speed & Cadance Sensors are compatible with the range of Garmin Edge Computers including the 1000, 810, 800, 510, 500, 910 XT, 310XT as well as the FR610 & FR70 sports watches.