... Built-in lithium polymer battery, battery capacity; 2500mAh2.The longest playing time, audio 28 hours, video 6 to 7 hours e- ... , listen, play set, the order of play, random play Microsoft audio, 3D, bass, volume, balance sound choices, the normal audio, Microsoft, rock, pop ... ,270 degree of support for background music playback.7.supports the video format, 720P high-definition decoding, support RM, AVI, ...