VT200 Single Ear Telephone Headset Operator Headset With Mic,Spec: 3.5mm Single Plug with Tuning 1. Up and down retractable headband, adapt to various head shapes 2. Using soft microphone cotton, can effectively reduce the background noise, more high definition and more comfortable calls. 3. The hose has the 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 wobble headset cable, pure copper impedance is low, the sound is not affected 6. Four plug design, compatible with a variety of devices Speaker parameters: 1. Size: 28mm diameter 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 Ohm 5. Sensitivity: -34DB 6. Frequency response: 100-3000HZ