The Wahoo TRACKR SPEED sensor is the sleek, magnet-less solution for capturing cycling speed data. It easily mounts to your bike's front wheel hub, and the Bluetooth Smart and ANT+ dual band technology allows you to connect to and display data on both smartphones and bike computers. Tracking speed data has never been this easy. Replaceable Battery - up to 200 hours of use Universal Fit - will fit most hub sizes Dual Band Technologs - supports ANT+ & Bluetooth wireless connections, to connect to both smartphones and bike computers Visible Connection - 2x LED lights show the sensor's device connection (blue) and speed detection (red) Tech Specs Physical Dimensions: W: 3.5cm x H: 3.2cm x D: 1.8cm Weight: 13 grams Battery: CR2032 Battery Life: Up to 200 hours Water Rating: IPX7 (submersion up to 1 meter for 30 minutes) Maximum Hub Diameter: 40mm Note: Speed Sensor is NOT compatible with spin bikes What’s Included TRACKR SPEED Sensor and Mount CR 2032 Battery (installed) Quick Start Guide Important Product Info Guide Setup Click here for TRACKR SPEED instructions Product Guides and Safety Information