1. Bluetooth Specification V2.1, Class2.
2. Operating Frequency Band: 2.4GHz ~ 2.48GHz unlicensed ISM band.
3. Support Multiple paired. (2 Bluetooth Phones can be paired meanwhile).
4. Integrated with echo cancellation and Noise suppressor.
5. One-Touch Answer, Call Rejection, Last Number Redial.
6. Advanced built-in louder speaker and microphone.
7. Rechargeable Lithium DC 3.7V, 650mAn (BL-5B).
8. Talking time: At least 16 hours.
9. Charging time: 2~3 hours.

Specification:

Bluetooth V2.1, Class 2
Bluetooth connective distance: 0-10 m.
Bluetooth frequency range: 2.402GHz-2.480GHz.
Rechargebale Battery: 650mAn
Microphone response: -49dB
Speaker Power: 1 w/4ohm.
Voltage input specification: DC3.6V-4.2V.
Normal current: 50mAn.
Operating temperature: -20c~+70c.