Blue SC Speed and Cadence Sensor.

The Wahoo BlueSC speed and cadence sensor transforms your phone into a powerful cycling computer. Using Bluetooth Smart and ANT+ technology, it tracks cycling speed, cadence, and distance which can be paired with your favorite cycling app including The Sufferfest and Zwift, or paired to your bike computer. It's weatherproof, small with a low drag profile, and comes with a rubber band and zip tie mounts.

Specs:

• Part Number: WFBTSC02
• Dimensions (LxWxH): 3.5" x 1" x 3"
• Weight: 36 grams
• Battery: CR2032
• Battery Life: Up to 12 Months
• Water Rating: IPX7 (waterproof up to 5 ft)
• Wireless Signal Strength: Up to 10 feet