BK9S Speed Sensor ±0.1km/h Accurate Measurement - Tracking and providing real-time cycling speed data on your bike computer or cycling apps with the COOSPO bike speed cycling sensor BK9S. BK9C Cadence Sensor ±1rpm Accurate Measurement - Tracking and providing real-time cycling cadence data on your bike computer or cycling apps with the COOSPO bike RPM cycling sensor BK9C. Cycling Cadence Sensor - The number of revolutions per minute (RPM) you complete at a given speed. By learning how to increase and train your cycling cadence, or the rate at which you pedal, you’ll improve your cycling efficiency and allow yourself to pedal for longer, faster. Easy to Install (NO MAGNETS) - Universal fit fits most bikes and frame sizes. The cadence speed sensor attaches to any bike's wheel hub. Mounts included. Recommended APP - Work with App Rouvy/Peloton/Wahoo. WAHOO APP NOT allow pairing 2 pcs of other brand’s cycling sensors at the same time. IP67 Waterproof - The COOSPO BK9 cadence speed sensor has an IP67 waterproof rating, allowing you to ride freely in any weather. COOSPO BK9 Cycling Cadence Sensor, Bluetooth 5.0 ANT+ Wireless Cycling RPM Cadence Sensor, IP67 Waterproof & 300H Battery, Compatible with Cycling Computers