Specifications:
<br />Model: TWS-K2
<br />Product Type: True Wireless (TWS) Bluetooth Stereo Headphone.
<br />Bluetooth Version: Bluetooth 4.1 (CSR)+ EDR; Class 2.
<br />Supports HSP, HFP, A2DP, AVRCP protocol.
<br />Battery Capacity Display, supports for iPhone.
<br />Frequency Response Range: 21Hz-18KHZ
<br />Operation Range: Up to 10 meters
<br />Microphone: Built-in high-sensitivity microphone (-38dB).
<br />Impedance: 16 
<br />Sensitivity: 95dB
<br />Degree of distortion:  1%
<br />SNR  95
<br />Headset Battery: 60mAh Rechargeable Li-ion battery
<br />Power Bank Box Battery: 1200mAh Rechargeable Li-ion battery
<br />Charge Time (for Power Bank Box): About 2.0 hours
<br />Music Playing Time: About 3 hours (The Music Volume will affect the time)
<br />Talk Time: About 4 hours
<br />Standby Time: 120 hours
<br />Charge Time:1 ~ 2 hours 
<br />
<br />Package content:
<br />1 x Wireless Bluetooth Headset   
<br />1 x USB Cable
<br />3 x Earbud