Specifications Model Aukey Ep-t25 Technology Bt 5 A2dp Avrcp Hfp Hsp Aac Driver (each Channel) 1 X 6mm / 0.24” Speaker Driver Sensitivity 90 ±3db Spl (at 1khz/1mw) Frequency Range 20hz – 20khz Impedance 16 Ohm ±15% Microphone Type Mems (microphone Chip) Microphone Sensitivity -38db ±1db (at 1khz) Frequency Range Microphone 100hz – 10khz Charging Time 1 Hour Battery Life Up To 5 Hours Battery Type Li-polymer (2 X 40mah) Operating Range 10m / 33ft Ip Rating Ipx5 Weight 7g (pair)