Garmin Bike Speed Sensor 2  

Transmitting over both Bluetooth and ANT+, this compact sensor provides accurate speed and distance data whether you�re riding outside or on a trainer. And, the Speed Sensor 2 will even track your ride when not paired to a phone or bike computer, synching that stored ride next time your phone or computer are in range. This Speed Sensor attaches to a standard hub on either wheel and self-calibrates to a compatible Garmin device. With no magnets or other exposed parts to line up, it�s a cinch to install, maintain and switch between bikes. Bluetooth and ANT+ secure digital transmission technology. Sensor memory allows the unit to track your rides, even when you aren�t using your phone or bike computer. The sensor will start a ride session when you start rolling and stop that session when you come to a stop, synching that ride to your phone (running Garmin Connect) or computer next time they are in range. CR2032 battery life is approximately 360 hours. Range is 10m. Waterproof to 10 meters (does not function unde