Review on XOSS X1 Bike Speed and Cadence Sensor: Wireless Bluetooth 4.0 Computer for Accurate Bicycle Speedometer (2 Pack) by Bobby Montoya

The sensor is only paired with the device for one or two sessions. To reconnect the device, it must be restarted by removing the battery with a coin. Removing the battery will also switch from one mode (cadence or speed) to another. Removing the battery is the only way to switch modes, there are no buttons or switches on the device. The only way to tell which mode the device is in is a small LED on the other side of the device, which only lights up briefly when the battery is inserted. Since the battery door is difficult to close and trying to fix the device's sensor requires many tries, accidentally switching modes during this process is inevitable.