Garmin GSC 10 Speed/Cadence Bike Sensor 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... 

Garmin GSC 10 Speed Cadence Bike Sensor 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. Part Number: 010-10644-00 User Ratings and Reviews 5 Stars Works as it should I bought... 

Garmin Edge 305 Cycling Computer with Heart Rate and Cadence The Edge 305 with heart rate and cadence lets you see whether you are training too hard or not enough. The heart rate monitor uses a robust ANT wireless technology that eliminates cross-talk and interference to reliably measure and send heart rate data to the Edge via a soft, comfortable chest strap....