The sensors can be paired to multiple devices...however when the attached club is out of your golf bag and exposed to light...the sensor can only actively pair to one device at a time. Anytime a paired CT-10 club sensor attached club is pulled out the golf bag, it will connect to the nearby device it is paired to.
If the CT-10 sensors are paired to two different compatible devices, you would need to ensure that the device you are not planning to use them with is powered off, if both devices the sensors are in the same location with the paired CT-10 sensors in range.
