RELATIVE TECHNOLOGY PARAMETER: Digital formats supported:MP3/WAV/WMAPC interface supported:USB2.0 Mfr estimated battery life:5 hours Battery tape/capacity: Bullt-in Lithium lon Polymer/3.7V.150m AHMaximum input power rating:5VDC Earphone output power:5mw Voice output frequency:20 Hz-20 Khz THD:0.05% Recharging time:2 hours Normally works current:30-35m A. Signal-to-noise ratio:87.2db Earphone impedance :16 Weight:52g Dimensions:172 160 40mm Extended Length of Earphonefixed lever:14mm Rotary degree of earphone fixed lever:270 deg; Rotary degree of earphone:90