Lenovo X9 supports single/binaural mode. The left and right earphones can be used separately. If one of your earphones has no sound, it may be set to single ear mode. You need to restore the binaural mode to use both earphones (specific setting method Please refer to the manual). In addition, you may check if there is a problem with your phone's audio source. Because some music and videos are output in mono, there is no sound from the left earphone.

Features:

• Brand Name: Lenovo
  
• Model Number: X9
  
• BT Version: 5.0
  
• Transmitting Distance: 10m/33ft
  
• Drive Diameter: 13mm
  
• Frequency Range: 20-20KHz
  
• Sensitivity: 119±3dB
  
• Impedance: 32Ω
  
• Charging Case Battery Capacity: 3.7V 300mAh
  
• Earbuds Battery Capacity (Each): 3.7V 30mAh
  
• Music Play Time: about 4 hours (depends on music volume)
  
• Charging Time: about 1.5 hours
• Earbud Weight (Each): 3.3g/0.11oz
  
• Package Size: 14.0 x 9.2 x 3.2cm/5.51 x 3.62 x 1.26in