This wireless Speed sensor tracks cycling cadence in real-time and helps you find the optimal speed,which making cycling easier and training more efficient. Features: Tracking speed data in real-time on your bike computer or smartphone with compatible training apps. Support to connect any BT5.0 or ANT+ enabled device and smart phones. Long battery life for you.Normal use is up to 300 hours. IPX7 waterproof,no fear of water and rain.You can ride in tough weather conditions. Small size,light weight and no magnet design. Easily install on your bike"'"s crank arm with the included rubber rings. Specification: Model: SPD70 Battery: 1* CR2025 (included) Wireless transmission: BT5.0 ; ANT+/2.4G Working time: approx. 300 hrs Waterproof: IPX7 Shock resistance: 1.5m Natural Drop Weight: approx. 7.8 g / 0.3 oz (includes battery)