Features: 1. Excellent sound quality， light weight， durable 2. Noise canceling， can reduce background noise 3. Hearing on two sides and microphone can be worn on either left or right ear 4. Very comfortable ear pad， comfortable for all day use 5. Adjustable headband， acoustic shock protection circuit Model number: XD600-02 Frequency range(Hz): 20¡«24KHz Fit design: over the ear Feature: volume control， microphone Color: black Interface: 4PIN RJ11 telephone crystal head With volume control and mute function 1. Wire Cable length: maximum length: about 2m Line breaking strength: not less than 10Lbs Tensile test: connecting portion of wire and pins， the wire and earphone case should be connected reliably， can endure 1.5Kg pulling force， no loose or fall off and can work normally Core structure: (8 / 0.1 + 250D) ¡Á 4 The total impedance: not more than 0.3¦¸ per meter 2. Speaker specification Type: moving-coil speaker Impedance: 150¦¸ Sensitivity: 118 ¡À 5dB at 20¦ÌPa = 0db， 1KHz Center frequency: 800 ¡À 50Hz Rated input power: 5mW Maximum input power: 30mW 3. Microphone Type: electret condenser microphone Impedance: 2.2K Sensitivity: -50 ¡À 3dB at 20¦ÌPa = 0db， 1KHz Frequency response: 30 ~ 16KHz 1 x Telephone headset In original package