Wireless Bluetooth Speaker with Rechargeable Battery. It is compatible with laptops, MP3/4 devices, TF/USB Flash Drive, or any audio device that is Bluetooth compatible or has a 3.5mm jack input. With the Bluetooth, it sends good interference-free performance, high data rate, high quality and efficiency. It comes with a Built-In FM Radio to listen to your favorite radio stations and with the Rechargeable Lithium Battery included, you can have up to 6 hours of playing time. Did we mention it comes with a Built-In Microphone? The Microphone will allow you to make and receive Hands-free calls and listen to the other person loud through the speaker. If you are playing your music and a call comes in, the music will stop and you will hear your phone ring and will continue playing after your call has ended.