... ,write 1000-900K Byte) Flash memory Built-in 4GB, Can be inserted above16GB. Add-in-TF card Power supply 1. 1200MAH Rechargeable ... songs in 60 hours or more MP3,WMA,WMV,ASF Headset maximum output:(L)10mW+(R)10mW(32Ohm) Music format Frequency response ... :20Hz---20KHzSNR(Signal Noise Ratio): 85DbSNR: 45dBMP1,MP2,MP3,WMA,WMV,ASF,WAV Operating temperature -5 To 40 degrees ...