Features:

• Cycling speed sensor for select Garmin wrist-mounted personal trainers and cycling computers
• Self-calibrating, wireless design measures both cycle speed and cadence in pedaling strokes per minute
• Provides up-to-the-minute feedback or captures results for later workout analysis
• Compatible with Garmin Edge 305, Edge 305CAD, and Forerunner 305
• Attaches easily to any bicycle; 1-year warranty

Editor Reviews:

Product Description:
Monitor your pedaling cadence as you ride with this self-calibrating, wireless speed/cadence sensor. It measures and reports your pedaling strokes per minute, providing feedback for optimal performance.

Amazon.com Product Description:
A good companion for Garmin's Edge 305 and 305CAD cycle computers and the Garmin Forerunner 305 personal trainer, the GSC 10 monitors your cycling rhythm for up-to-the-minute results and later analysis. The self-calibrating, wireless unit measures both speed (in pedaling strokes per minute) and cadence , then provides feedback to the user for optimal performance. You can later feed the results to Garmin's Training Center software, which helps you tailor your workouts to meet specific goals and objectives.

Like the Garmin heart rate monitor, the GSC 10 attaches easily to your bike, where its sensors detect signals from your wheels and send the information wirelessly to your personal trainer/cycle computer. It's also backed by a one-year warranty.

Rating : - Design flaw
When placing the sensor, it turns out that there is too much tilt towards the crank. After one bump on the road, or hitting it with my road shoe, the arm of the sensor moved and the spokes hit it and broke it off. I am now on my second sensor.