Built-in Li-ion battery, directly connect with PC for re-charging. Play time: 3-4 hours. Also can be uses as USB Flash Drive (You can use it to store any data / files). Specifics: Size: 4.3*3*1.4CM Headphone Jack: 3.5mm stereo Jack USB data storage, supporting USB 2.0. Stylish design in a compact plastic case with a clip. Easy to clip-on to anything. No Built-in Memory. Support music format: MP3. Package List 1 x Clip MP3 Playe No bulit-in memory in the player, it can only play music when insert TF card 1Scratch-proof shell provides you comfortable hand-feel, and the case has strong resistance to pressure and impact, touch button makes it easy to operate the player, you could enjoy music at anytime and anywhere. 2 Compact and stylish mp3 player, clip design, easy to carry. 3 Built in rechargeable lithium battery, environmental friendly 4 Support for multiple MP3 music format of digital music play