VT200D Double Ears Telephone Headset Operator Headset With Mic,Spec: Crystal Head 6-wire Sequence 1. Up and down retractable headband, adapt to a variety of head shape 2. Using soft microphone cotton, can effectively reduce the background noise, talk more high definition and more comfortable. 3. The hose has resistance to bending, you can adjust the hose to the position you think comfortable. 4. Comfortable ear cushions, fine texture, removable and replaceable 5. Durable and resistant to swing headset cable, pure copper impedance is low, the sound is not affected 6. 5 kinds of plug design, compatible with a variety of devices Speaker parameters: 1. Size: diameter 28mm 2. Distortion: less than 0.1% 3. Impedance: 150 ohms 4. Sensitivity: 118DB+-3DB 5. Frequency response: 200-4000HZ Microphone parameters: 1. Microphone: omnidirectional 2. Signal-to-noise ratio: greater than or equal to 52DB 3. Distortion: less than 0.1% 4. Impedance: 2200 ohms 5. Sensitivity: -34DB 6. Frequency response: 100-3000HZ