Before leaving the factory, please make sure that each device has undergone rigorous testing to ensure that all products can guarantee 100% high quality before leaving the factory. thank you very much! ! !
 
 
Switching between Chinese and English: Double-click the headset after powering on and before connecting Start SIEI: Press and hold for 2 seconds, after a beep, start SIEI Switch up and down song: Double-click the left ear to switch to the next song. Double click on the right ear to switch to the previous song Adjust the volume: triple-click the left earphone to increase the volume. Triple-click the right earphone to decrease the volume. Answering/hanging up a call: Short press the function key to answer the call. Long press the function button for 2 seconds to hang up Transmission distance:> 10M Talk time: 3-4 hours Playing time: 3-4 hours Charging time: 1-2 hours Support system: Therefore, devices and mobile phones that support Bluetooth