Call conversation through Bluetooth can be recorded and stored in the built-in memory card. Bluetooth superior feature. The music mutes automatically when there is a call and continues after hang up. Reject call. Last call redial. Voice dial support. 2.5mm jack for external earphone line. Built-in MP3 player. Support T-falsh card for enlarging memory. Support MP3 file play of TF card. Flash USB connector for transmite file. Bluetooth V2.0 transmitted power: Class 2 (max 4dBm). Bluetooth receive sensitivity: - 80dBm. Bluetooth battery rechargeable 460mAh lu-ion battery. Bluetooth power supply: DC 5V. Bluetooth continuous talking time over 15 hours. Bluetooth operation range: within 10 meters. MP3 audio format support: MP3/WMA/WAV. External memory enlarge: TF card (Max 2G). MP3 continuous play time about 10 hours. MP 3 frequency response: 20Hz-20KHz. MP 3 record sampling rate: 64Kbps/8KHz. MP3 record format: WAV.