Bionic includes two functions, namely free calling and environmental sensing. When switching, you only need to press the left ear unit once (free calling) and twice (environmental sensing). It can be achieved. Because JBL UA FLASH is an in-ear headset, it has a good passive noise reduction effect. After wearing the ear, it is almost impossible to hear other sounds in the environment. After "Free Talk" is turned on, the music will be reduced. Until there is only a little bit of sound, then turn on the microphone on the headset to receive the external sound. In this way, it will be transmitted to your ears, so that you can communicate with others without taking off the headset. Communication; when "Environment Sensing" is turned on, the volume of music playback will only be reduced a little, and at the same time, the surrounding environment can be heard clearly. At this time, it will not affect listening to music, and you can also hear ambient sounds. Although the functions of the two are similar, the application scenarios are still somewhat different. For example, when someone wants to communicate with you, you can turn on "Free Call". At this time, the music is almost inaudible, and you can fully focus on communicating with others. And if you want to wear it for a run or something outdoors, it is recommended to turn on "environmental sensing". Music and ambient sounds will be transmitted to your ears at the same time, making it safer when exercising.