Specifications: SPEAKER: Frequency Response:20~20000Hz. Sensitivity: 105+/-3dB. Impedance:32(ohm)+/-15% at 1kHz. Max Input:10mw MICROPHONE: Frequency Response:50~20000Hz. Sensitivity:-58+/-2dB F=1kHz P=1Pa Rated:DC4.5V Min Operation Voltage:DC1.0V Description: Adjustable boom microphone.(Suitable also for PDA earphone, PC earphone and Two-Way Radio earphone). Character: Super light, comfortable, easy use with convenient ear hook for both right and left ear, and provides clear communication. packing list : DESCRIPTION : Single track Mobie ear-hook UNIT PACKAGE : OPP PCS /CTN : 500 CTN SIZE(CM) : 40*30*32 G.W.(KGS) : 12.5