This Bluetooth Portable speaker including Handsfree is only 8cm in diameter. It includes a built-in MP3 player. Either pair this speaker with your bluetooth mobile phone/laptop/tablet or MP3 player for music anywhere or insert a TF/Micro SD card (not included) to use the built-in MP3 player. You can also use the included cable to plug in any source with a 3.5mm headphone socket. You can adjust volume and skip tracks forward and backwards