RaceFit CRE001B1 Sensor module is a wireless device that allows you to track your performance during sports activities and monitor your progress over time. It can be used for a variety of sports, including running, cycling, swimming, and more. The device connects to your smartphone via Bluetooth, and you can use the RaceFit app to view your data and track your goals. The module can measure your speed, distance, pace, and calories burned. It can also track your heart rate and provide GPS tracking.