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.