Another important point of the Bluetooth headset depends on the transmission distance, which is independent of the Bluetooth version and depends on the Bluetooth technology Power Class. Most mobile phones and mobile devices use the Power Class 2 standard transmission distance of 10 meters. The upgraded Power Class 1 increases the transmission distance to 100 meters. Both versions support the A2DP stereo transmission protocol, which can be used with stereo headphones interconnected. In general, the distance between a mobile phone and a Bluetooth headset will not be too far away. If there are no large obstacles in the middle, the transmission quality will be very good within 7 meters. Breakpoints exceeding 8 meters will occur and more than 10 meters will be between Bluetooth devices. Will lose connection.