Garmin Bike Speed Sensor 2

Monitor your speed as you ride with this easy-to-install wireless sensor. With no magnets or other exposed parts to line up, this sensor is easy to install, maintain and move between bikes.
The Speed Sensor 2 attaches to the hub of either wheel. You can set up wheel size in our Garmin Connect^™ online community or self-calibrate with an Edge^® cycling computer or compatible Garmin device. Once set up, you'll get accurate speed and distance at all times — even without a head unit.