Sports USB rechargeable MP3 player headset is very convenient extremely well built and very comfortable. You can enjoy music at any moment without headphone cable. The voice comes with good volume long lasting battery and is very flexible. Very useful TF-SD Card slot supports up to 4 GB. Get one and enjoy wonderful music as you are doing sports. - Making it ideal for use during jogging/gym work etc. - Playback formats: MP3 - Includes build in rechargeable lithium battery with 3 hours playing time - No build-in memory support max. 4GB TF card - On/Off/Volume up/down and Next/Previous buttons - Interfaces: 1* USB 5-Pin socket 1*TF card slot - USB charging cable included