Easily monitor your speed with this easy-to-install hub mounted sensor from Garmin-just pair up & go. The Speed Sensor is incredibly easy to use. Attach it to the hub of either wheel & it will self-calibrate with your Edge computer or other compatible device to provide you with relialble & accurate speed & distance readings. Theres no need to faff around with magnets & the rest. The simple design makes it easy to switch between bikes, too. The sensor can be used without a head unit & can be paired direct with a phone or tablet-perfect for training software such as Zwift.