Main indicators and performance: Conversion mode: capacitive Frequency response: 100Hz~16000Hz Output impedance: low impedance Directivity: single direction Sensitivity: -45dB±2dB. Power supply voltage: DC3V<br><br>How to use: 1. Press the "+" and "-" signs on the microphone battery case, install the battery correctly and connect the audio output cable. 2. First, turn the volume of the power amplifier to the "0" position, then turn on the power switches of the power amplifier and conference microphone, and then slowly adjust the volume of the power amplifier until the volume reaches a suitable level. 3. The sound pickup effect of the sound head is 30CM away from the sound head, and it should be kept at about 30CM from the sound head when teaching. Things to note: 1. Do not point the microphone's sound head toward the speaker to avoid feedback. 2. Do not increase the volume too high to avoid feedback. 3. If the microphone is not used for a period of time, please take out the battery to prevent battery fluid from corroding the mechanical color: Black material: plastic<br><br>Package Contents: 1 x Gooseneck Microphone 1 x Adapter 1 x audio cable 2 x Battery<br><br>Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.