Immerse yourself in your world. Whether you’re tuned into music or taking calls, you’ve got no cords to hold you back. Dual Connect lets you use either earbuds, or both, anytime you want, in stereo or mono mode. Your favourite artists sound incredible with Pure Bass. With up to 3-4 hours of battery life and a comfortable fit, you can keep the fun going all day and night. And if you miss the world, you can take and end calls or talk to your voice assistant using just a finger. Simple as that! TWS-4 is compatible with all mobile phone,music players, Portable gaming devices Built-in Mic with Answer/Call end/Multi functional button Very easy so switch between call and musics… TWS-4 wireless headset is a latest Bluetooth 5.0 earbuds. Wide range compatibility for all smartphones.PLEASE NOTE:TWS-4 can operate as either one earbuds or both Earbuds. If it is only one earbuds functioning and the other is silent it's either its battery is low or the other is acting as one earbuds. For better results for both Earbuds to function, please ensure to charge the dock fully together with the Earbuds at which the Earbuds will switch themselves off from charging state(red) and the dock will stop blinking(blue illumination).At this state of fully charged, press the button within the dock to wake the Earbuds from the off state at which the Earbuds are ready to be paired together. When taken out of the charging dock both Earbuds will be blinking red and blue alternative but one earbuds will pair with the other and stop blinking. The remaining blinking Earbuds is now ready to be paired to the Bluetooth of any bluetooth-enabled devices at which the blinking will also stop.The JBL TWS-4 is One-touch Control device, touch any Earbuds to pause or start playing the music.