How to Use: Plug and Play Specification: Item Type: Telephone Headset Model: H600D-2.5-MV Material: ABS Colour: Black Plug Type: 2.5mm Speaker Parameters: Sensitivity: 105±3dB (at 178mV 1KHz) Voice Coil Impedance: 150±15? (at 1KHz) Frequency Characteristics: 100Hz-10KHz Distortion: ?5% (at 178mV 1KHz) Microphone Parameters: Directivity: Single Direction Sensitivity: -40±2dB (2.0V, 2.2K?, 1KHz) Distortion: ?5% (at 4.5V 2.2K? 1KHz) Frequency Characteristic: 200Hz-6KHz Support Volume Adjustment and Microphone Mute Applicable Device: Landline Phone or Cordless Dect Phone with 2.5mm Headphone Jack Package List: 1 X Telephone Headset 1 X Manual