Garmin speed sensor. 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. this speed sensor attaches to the hub of either wheel. you can set up wheel size in the 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. includes new battery. this unit comes with ANT+ connectivity and BLUETOOTH technology allowing you to sync to Garmin Connect and other training apps, compatible devices. compare new at $70.00. will accept cash or venmo.