1.Speaker diameter: 40 milimeters 
2.Impedance: 32 Ohms
3.Sensitivity: 108dB S.P.L.at 1KHz;
4.Rated power:20mW
5.Aggregate capability:50mW
6.Frequency Response:20Hz-20,000Hz
7.Microphone Unit:6*5mm
8.Impedance:less than 2.2KOhms
9.Frequancy Response:30Hz-16,000Hz
10.Operating voltage:4.5V 
11.Charging Time:2-3 hours 
12.Talking time:8 hours