USB disk function MP3 player Quartz mp3 watch with LCD. Show function on the LCD 10 hours playing for fully charged batteries Memory: built-in 64/128M to 2G flash chip Battery: built-in 150mAH, 3.7V Hi Li-ion rechargeable battery Charging time: up to 2.5-3 hours and up to 5-6 hours for first-time charging